Methods and Systems for Determining a Critical Dimension and Overlay of a Specimen

ABSTRACT

Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including: but not limited to, critical dimension and overlay misregistration; defects and thin film characteristics; critical dimension and defects; critical dimension and thin film characteristics; critical dimension, thin film characteristics and defects; macro defects and micro defects; flatness, thin film characteristics and defects; overlay misregistration and flatness; an implant characteristic and defects; and adhesion and thickness. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to methods and systems forsemiconductor fabrication processes. Certain embodiments relate to amethod and a system for evaluating and/or controlling a semiconductorfabrication process by determining at least two properties of aspecimen.

2. Description of the Related Art

Fabrication of semiconductor devices such as logic and memory devicestypically includes a number of processes that may be used to formvarious features and multiple levels or layers of semiconductor deviceson a surface of a semiconductor wafer or another appropriate substrate.For example, lithography is a process that typically involvestransferring a pattern to a resist arranged on a surface of asemiconductor wafer. Additional examples of semiconductor fabricationprocesses may include chemical-mechanical polishing, etch, deposition,ion implantation, plating, and cleaning. Semiconductor devices aresignificantly smaller than a typical semiconductor wafer or substrate,and an array of semiconductor devices may be formed on a semiconductorwafer. After processing is complete, the semiconductor wafer may beseparated into individual semiconductor devices.

Semiconductor fabrication processes, however, are among the mostsophisticated and complex processes used in manufacturing. In order toperform efficiently, semiconductor fabrication processes may requirefrequent monitoring and careful evaluation. For example, semiconductorfabrication processes may introduce a number of defects (e.g.,non-uniformities) into a semiconductor device. As an example, defectsmay include contamination introduced to a wafer during a semiconductorfabrication process by particles in process chemicals and/or in a cleanroom environment. Such defects may adversely affect the performance ofthe process to an extent that overall yield of the fabrication processmay be reduced below acceptable levels. Therefore, extensive monitoringand evaluation of semiconductor fabrication processes may typically beperformed to ensure that the process is within design tolerance and toincrease the overall yield of the process. Ideally, extensive monitoringand evaluation of the process may take place both during processdevelopment and during process control of semiconductor fabricationprocesses.

As features sizes of semiconductor devices continue to shrink, a minimumfeature size that may be fabricated may often be limited by theperformance characteristics of a semiconductor fabrication process.Examples of performance characteristics of a semiconductor fabricationprocess include, but are not limited to, resolution capability, acrosschip variations, and across wafer variations. In optical lithography,for example, performance characteristics such as resolution capabilityof a lithography process may be limited by the quality of the resistapplication, the performance of the resist material, the performance ofthe exposure tool, and the wavelength of light used to expose theresist. The ability to resolve a minimum feature size, however, may alsobe strongly dependent on other critical parameters of the lithographyprocess such as a temperature of a post exposure bake process and anexposure dose of an exposure process. As such, controlling theparameters of processes that may be critical to the resolutioncapability of a semiconductor fabrication process such as a lithographyprocess is becoming increasingly important to the successful fabricationof semiconductor devices.

As the dimensions of semiconductor devices continue to shrink withadvances in semiconductor materials and processes, the ability toexamine microscopic features and to detect microscopic defects has alsobecome increasingly important to the successful fabrication ofsemiconductor devices. Significant research has been focused onincreasing the resolution limit of metrology and/or inspection toolsused to examine microscopic features and defects. There are severaldisadvantages, however, in using the currently available methods andsystems for metrology and/or inspection of specimens fabricated bysemiconductor fabrication processes. For example, multiple stand-alonemetrology/inspection systems may be used for metrology and/or inspectionof specimens fabricated by such processes. As used herein, “stand-alonemetrology/inspection system” may generally refer a system that is notcoupled to a process tool and is operated independently of any otherprocess tools and/or metrology/inspection systems. Multiplemetrology/inspection systems, however, may occupy a relatively largeamount of clean room space due to the footprints of each of themetrology and/or inspection systems.

In addition, testing time and process delays associated with measuringand/or inspecting a specimen with multiple metrology/inspection systemsmay increase the overall cost of manufacturing and the manufacturingtime for fabricating a semiconductor device. For example, process toolsmay often be idle while metrology and/or inspection of a specimen isperformed such that the process may be evaluated before additionalspecimens are processed thereby increasing manufacturing delays.Furthermore, if processing problems can not be detected beforeadditional wafers have been processed, wafers processed during this timemay need to be scrapped, which increases the overall cost ofmanufacturing. Additionally, buying multiple metrology/inspectionsystems increases the cost of fabrication.

In an additional example, for in situ metrology and/or inspection usingmultiple currently available systems, determining a characteristic of aspecimen during a process may be difficult if not impossible. Forexample, measuring and/or inspecting a specimen with multiple currentlyavailable systems during a lithography process may introduce a delaytime between or after process steps of the process. If the delay time isrelatively long, the performance of the resist may be adverselyaffected, and the overall yield of semiconductor devices may be reduced.As such, there may also be limitations on process enhancement, control,and yield of semiconductor fabrication processes due to the limitationsassociated with metrology and/or inspection using multiple currentlyavailable systems. Process enhancement, control, and yield may also belimited by an increased potential for contamination associated withmetrology and/or inspection using multiple currently availablemetrology/inspection systems. In addition, there may be practical limitsto using multiple metrology/inspection systems in semiconductormanufacturing processes. In an example, for in situ metrology and/orinspection using multiple currently available systems, integratingmultiple metrology/inspection systems into a process tool or a clustertool may be difficult due to the availability of space within the tool.

SUMMARY OF THE INVENTION

An embodiment relates to a system that may be configured to determine atleast two properties of a specimen. The system may include a stageconfigured to support the specimen. The system may also include ameasurement device coupled to the stage. The measurement device mayinclude an illumination system configured to direct energy toward asurface of the specimen. The measurement device may also include adetection system coupled to the illumination system. The detectionsystem may be configured to detect energy propagating from the surfaceof the specimen. The measurement device may also be configured togenerate one or more output signals in response to the detected energy.The system may also include a processor coupled to the measurementdevice. The processor may be configured to determine at least a firstproperty and a second property of the specimen from the one or moreoutput signals.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include overlay misregistration ofthe specimen. In addition, the processor may be configured to determinea third and/or a fourth property of the specimen from the one or moreoutput signals. For example, a third property of the specimen mayinclude a presence of defects on the specimen, and the fourth propertyof the specimen may include a flatness measurement of the specimen. Inan embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, a brightfield non-imaging device, a dark field non-imaging device, a brightfield and dark field non-imaging device, a coherence probe microscope,an interference microscope, an optical profilometer, or any combinationthereof. In this manner, the measurement device may be configured tofunction as a single measurement device or as multiple measurementdevices. Because multiple measurement devices may be integrated into asingle measurement device of the system, optical elements of a firstmeasurement device, for example, may also be optical elements of asecond measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or a remote controller computer coupled tothe local processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the local processor. In addition, theremote controller computer may be configured to determine at least thefirst property and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine the third propertyand/or the fourth property of the specimen from the at least partiallyprocessed one or more output signals. In an additional embodiment, theremote controller computer may be coupled to a process tool such as asemiconductor fabrication process tool. In this manner, the remotecontroller computer may be further configured to alter a parameter ofone or more instruments coupled to the semiconductor fabrication processtool in response to at least the determined first or second property ofthe specimen using an in situ control technique, a feedback controltechnique, or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen. The method may also include detectingenergy propagating from the surface of the specimen. The method mayfurther include generating one or more output signals in response to thedetected energy. Furthermore, the method may include processing the oneor more output signals to determine at least a first property and asecond property of the specimen.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include overlay misregistration ofthe specimen. In addition, the method may further include processing theone or more output signals to determine a third and/or a fourth propertyof the specimen. For example, a third and a fourth property of thespecimen may include a presence of defects on the specimen and aflatness measurement of the specimen. In an additional embodiment, asemiconductor device may be fabricated by the method. For example, themethod may include forming a portion of a semiconductor device upon thespecimen.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may further include generating one or moreoutput signals in response to the detected energy. Thecomputer-implemented method may further include processing the one ormore output signals to determine at least a first property and a secondproperty of the specimen. For example, the first property may include acritical dimension of the specimen. Furthermore, the second property mayinclude overlay misregistration of the specimen. Thecomputer-implemented method may also include processing the one or moreoutput signals to determine a third and/or fourth properties of thespecimen. In an example, the third and fourth properties of the specimenmay include a presence of defects on the specimen and a flatnessmeasurement of the specimen.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a presence of defectson specimen. The second property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a beam profile ellipsometer,a bright field imaging device, a dark field imaging device, a brightfield and dark field imaging device, a bright field non-imaging device,a dark field non-imaging device, a bright field and dark fieldnon-imaging device, a double dark field device, a dual beamspectrophotometer, a coherence probe microscope, an interferencemicroscope, an optical profilometer, or any combination thereof. In thismanner, the measurement device may be configured to function as a singlemeasurement device or as multiple measurement devices. Because multiplemeasurement devices may be integrated into a single measurement deviceof the system, optical elements of a first measurement device, forexample, may also be optical elements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen. The method may also include detectingenergy propagating from the surface of the specimen. The method mayfurther include generating one or more output signals in response to thedetected energy. Furthermore, the method may include processing the oneor more output signals to determine at least a first property and asecond property of the specimen.

In an embodiment, the first property may include a presence of defectson specimen. The second property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a presence ofdefects on specimen. The second property may include a thin filmcharacteristic of the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a presence of defectson specimen. The second property may include a critical dimension of thespecimen. In addition, the processor may be configured to determineother properties of the specimen from the one or more output signals. Inan embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, a brightfield non-imaging device, a dark field non-imaging device, a brightfield and dark field non-imaging device, a coherence probe microscope,an interference microscope, an optical profilometer, or any combinationthereof. In this manner, the measurement device may be configured tofunction as a single measurement device or as multiple measurementdevices. Because multiple measurement devices may be integrated into asingle measurement device of the system, optical elements of a firstmeasurement device, for example, may also be optical elements of asecond measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include a presence of defectson specimen. The second property may include a critical dimension of thespecimen. In addition, the processor may be configured to determineother properties of the specimen from the one or more output signals. Inan additional embodiment, a semiconductor device may be fabricated bythe method. For example, the method may include forming a portion of asemiconductor device upon a specimen such as a semiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a presence ofdefects on specimen. The second property may include a criticaldimension of the specimen. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a beam profile ellipsometer,a dual beam spectrophotometer, a bright field imaging device, a darkfield imaging device, a bright field and dark field imaging device, abright field and/or dark field non-imaging device, a coherence probemicroscope, an interference microscope, an optical profilometer, or anycombination thereof. In this manner, the measurement device may beconfigured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or a remote controller computer coupled tothe local processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the local processor. In addition, theremote controller computer may be configured to determine at least thefirst property and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a criticaldimension of the specimen. The second property may include a thin filmcharacteristic of the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals.

An embodiment relates to a system configured to determine at least threeproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property, a second property and a thirdproperty of the specimen from the one or more output signals.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include a presence of defects onthe specimen. The third property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a beam profile ellipsometer,a bright field imaging device, a dark field imaging device, a brightfield and dark field imaging device, a bright field and/or dark fieldnon-imaging device, a coherence probe microscope, an interferencemicroscope, an optical profilometer, a dual beam spectrophotometer, orany combination thereof. In this manner, the measurement device may beconfigured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or a remote controller computer coupled tothe local processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty, the second property and the third property of the specimenfrom the at least partially processed one or more output signals.Furthermore, the remote controller computer may be configured todetermine additional properties of the specimen from the at leastpartially processed one or more output signals. In an additionalembodiment, the remote controller computer may be coupled to a processtool such as a semiconductor fabrication process tool. In this manner,the remote controller computer may be further configured to alter aparameter of one or more instruments coupled to the semiconductorfabrication process tool in response to at least the determined first,second, or third property of the specimen using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

An additional embodiment relates to a method for determining at leastthree properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property, a secondproperty, and a third property of the specimen.

In an embodiment, the first property may include a critical dimension ofthe specimen. The second property may include a presence of defects onthe specimen. The third property may include a thin film characteristicof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property, a second property and a third property of thespecimen may include at least partially processing the one or moreoutput signals using a local processor. The local processor may becoupled to the measurement device. Processing the one or more outputsignals may also include sending the partially processed one or moreoutput signals from the local processor to a remote controller computer.In addition, processing the one or more output signals may includefurther processing the partially processed one or more output signalsusing the remote controller computer. In an additional embodiment, theremote controller computer may be coupled to a process tool such as asemiconductor fabrication process tool. In this manner, the method mayinclude altering a parameter of one or more instruments coupled to theprocess tool using the remote controller computer in response to atleast the determined first or second property of the specimen. Alteringthe parameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least three propertiesof a specimen. The system may include a measurement device. In thismanner, controlling the system may include controlling the measurementdevice. In addition, the measurement device may include an illuminationsystem and a detection system. The measurement device may also becoupled to a stage. Controlling the measurement device may includecontrolling the illumination system to direct energy toward a surface ofthe specimen. Additionally, controlling the measurement device mayinclude controlling the detection system to detect energy propagatingfrom the surface of the specimen. The method may also include generatingone or more output signals in response to the detected energy. Thecomputer-implemented method may further include processing the one ormore output signals to determine at least a first property, a secondproperty and a third property of the specimen. For example, the firstproperty may include a critical dimension of the specimen. The secondproperty may include a presence of defects on the specimen. The thirdproperty may include a thin film characteristic of the specimen. Inaddition, the processor may be configured to determine other propertiesof the specimen from the one or more output signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a presence of macrodefects on the specimen. The second property may a presence of microdefects on the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a bright field imagingdevice, a dark field imaging device, a bright field and dark fieldimaging device, a bright field and/or dark field non-imaging device, adouble dark field device, a coherence probe microscope, an interferencemicroscope, an optical profilometer, or any combination thereof. In thismanner, the measurement device may be configured to function as a singlemeasurement device or as multiple measurement devices. Because multiplemeasurement devices may be integrated into a single measurement deviceof the system, optical elements of a first measurement device, forexample, may also be optical elements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device or a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may also includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include a presence of macrodefects on the specimen. The second property may be a presence of microdefects on the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a presence ofmacro defects on the specimen. The second property may be a presence ofmicro defects on the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals.

An embodiment relates to a system configured to determine at least threeproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property, a second property and a thirdproperty of the specimen from the one or more output signals.

In an embodiment, the first property may include a flatness measurementof the specimen. The second property may include a presence of defectson the specimen. The third property may include a thin filmcharacteristic of the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an embodiment, the measurement device mayinclude a non-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a beam profile ellipsometer,a bright field and/or dark field imaging device, a bright field and/ordark field non-imaging device, a double dark field device, a coherenceprobe microscope, an interference microscope, an interferometer, anoptical profilometer, a dual beam spectrophotometer, or any combinationthereof. In this manner, the measurement device may be configured tofunction as a single measurement device or as multiple measurementdevices. Because multiple measurement devices may be integrated into asingle measurement device of the system, optical elements of a firstmeasurement device, for example, may also be optical elements of asecond measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty, the second property and the third property of the specimenfrom the at least partially processed one or more output signals.Furthermore, the remote controller computer may be configured todetermine additional properties of the specimen from the at leastpartially processed one or more output signals. In an additionalembodiment, the remote controller computer may be coupled to a processtool such as a semiconductor fabrication process tool. In this manner,the remote controller computer may be further configured to alter aparameter of one or more instruments coupled to the process tool inresponse to at least the determined first second or third property ofthe specimen using an in situ control technique, a feedback controltechnique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leastthree properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property, a secondproperty, and a third property of the specimen.

In an embodiment, the first property may include a flatness measurementof the specimen. The second property may include a presence of defectson the specimen. The third property may include a thin filmcharacteristic of the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an additional embodiment, a semiconductor devicemay be fabricated by the method. For example, the method may includeforming a portion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property, a second property and a third property of thespecimen may include at least partially processing the one or moreoutput signals using a local processor. The local processor may becoupled to the measurement device. Processing the one or more outputsignals may also include sending the partially processed one or moreoutput signals from the local processor to a remote controller computer.In addition, processing the one or more output signals may includefurther processing the partially processed one or more output signalsusing the remote controller computer. In an additional embodiment, theremote controller computer may be coupled to a process tool such as asemiconductor fabrication process tool. In this manner, the method mayinclude altering a parameter of one or more instruments coupled to theprocess tool using the remote controller computer in response to atleast the determined first or second property of the specimen. Alteringthe parameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least three propertiesof a specimen. The system may include a measurement device. In thismanner, controlling the system may include controlling the measurementdevice. In addition, the measurement device may include an illuminationsystem and a detection system. The measurement device may also becoupled to a stage. Controlling the measurement device may includecontrolling the illumination system to direct energy toward a surface ofthe specimen. Additionally, controlling the measurement device mayinclude controlling the detection system to detect energy propagatingfrom the surface of the specimen. The method may also include generatingone or more output signals in response to the detected energy. Thecomputer-implemented method may further include processing the one ormore output signals to determine at least a first property, a secondproperty and a third property of the specimen. For example, the firstproperty may include a flatness measurement of the specimen. The secondproperty may include a presence of defects on the specimen. The thirdproperty may include a thin film characteristic of the specimen. Inaddition, the processor may be configured to determine other propertiesof the specimen from the one or more output signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the detected light.

In an embodiment, the first property may include overlay misregistrationof the specimen. The second property may include a flatness measurementof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, aspectroscopic ellipsometer, a beam profile ellipsometer, a bright fieldimaging device, a dark field imaging device, a bright field and darkfield imaging device, a coherence probe microscope, an interferencemicroscope, an interferometer, an optical profilometer, a dual beamspectrophotometer, or any combination thereof. In this manner, themeasurement device may be configured to function as a single measurementdevice or as multiple measurement devices. Because multiple measurementdevices may be integrated into a single measurement device of thesystem, optical elements of a first measurement device, for example, mayalso be optical elements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include overlay misregistrationof the specimen. The second property may include a flatness measurementof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include overlaymisregistration of the specimen. The second property may include aflatness measurement of the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may also be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a characteristic of animplanted region of the specimen. The second property may include apresence of defects on the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an embodiment, the measurement device mayinclude a modulated optical reflectometer, an X-ray reflectance device,an eddy current device, a photo-acoustic device, a spectroscopicellipsometer, a spectroscopic reflectometer, a dual beamspectrophotometer, a non-imaging scatterometer, a scatterometer, aspectroscopic scatterometer, a reflectometer, an ellipsometer, anon-imaging bright field device, a non-imaging dark field device, anon-imaging bright field and dark field device, a bright field imagingdevice, a dark field imaging device, a bright field and dark fieldimaging device, or any combination thereof. In this manner, themeasurement device may be configured to function as a single measurementdevice or as multiple measurement devices. Because multiple measurementdevices may be integrated into a single measurement device of thesystem, optical elements of a first measurement device, for example, mayalso be optical elements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include a characteristic of animplanted region of the specimen. The second property may include apresence of defects on the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an additional embodiment, a semiconductor devicemay be fabricated by the method. For example, the method may includeforming a portion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to thesemiconductor fabrication process tool using the remote controllercomputer in response to at least the determined first or second propertyof the specimen. Altering the parameter of the instruments may includeusing an in situ control technique, a feedback control technique, and/ora feedforward control technique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a characteristicof an implanted region of the specimen. The second property may includea presence of defects on the specimen. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may be configured to generate one or more output signals inresponse to the detected light. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include an adhesioncharacteristic of the specimen. The second property may include athickness of the specimen. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals. In an embodiment, the measurement device may include aneddy current device, a photo-acoustic device, a spectroscopicellipsometer, an ellipsometer, an X-ray reflectometer, a grazing X-rayreflectometer, an X-ray diffractometer, or any combination thereof. Inthis manner, the measurement device may be configured to function as asingle measurement device or as multiple measurement devices. Becausemultiple measurement devices may be integrated into a single measurementdevice of the system, optical elements of a first measurement device,for example, may also be optical elements of a second measurementdevice.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the local processor. In addition, theremote controller computer may be configured to determine at least thefirst property and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe semiconductor fabrication process tool in response to at least thedetermined first or second property of the specimen using an in situcontrol technique, a feedback control technique, and/or a feedforwardcontrol technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include an adhesioncharacteristic of the specimen. The second property may include athickness of the specimen. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals. In an additional embodiment, a semiconductor device maybe fabricated by the method. For example, the method may include forminga portion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include an adhesioncharacteristic of the specimen. The second property may include athickness of the specimen. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals.

An embodiment relates to a system configured to determine at least twoproperties of a specimen. The system may include a stage configured tosupport the specimen. The system may also include a measurement devicecoupled to the stage. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to detectenergy propagating from the surface of the specimen. The measurementdevice may be configured to generate one or more output signals inresponse to the detected energy. The system may also include a processorcoupled to the measurement device. The processor may be configured todetermine at least a first property and a second property of thespecimen from the one or more output signals.

In an embodiment, the first property may include a concentration of anelement in the specimen. The second property may include a thickness ofthe specimen. In addition, the processor may be configured to determineother properties of the specimen from the one or more output signals. Inan embodiment, the measurement device may include a photo-acousticdevice, an X-ray reflectometer, a grazing X-ray reflectometer, an X-raydiffractometer, an eddy current device, a spectroscopic ellipsometer, anellipsometer, or any combination thereof. In this manner, themeasurement device may be configured to function as a single measurementdevice or as multiple measurement devices. Because multiple measurementdevices may be integrated into a single measurement device of thesystem, optical elements of a first measurement device, for example, mayalso be optical elements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine at least the firstproperty and the second property of the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining at leasttwo properties of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a surface of the specimen using the illumination system. Themethod may also include detecting energy propagating from the surface ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine at least a first property and a secondproperty of the specimen.

In an embodiment, the first property may include a concentration of anelement in the specimen. The second property may include a thickness ofthe specimen. In addition, the processor may be configured to determineother properties of the specimen from the one or more output signals. Inan additional embodiment, a semiconductor device may be fabricated bythe method. For example, the method may include forming a portion of asemiconductor device upon a specimen such as a semiconductor substrate.

In an embodiment, processing the one or more output signals to determineat least a first property and a second property of the specimen mayinclude at least partially processing the one or more output signalsusing a local processor. The local processor may be coupled to themeasurement device. Processing the one or more output signals may alsoinclude sending the partially processed one or more output signals fromthe local processor to a remote controller computer. In addition,processing the one or more output signals may include further processingthe partially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to at least thedetermined first or second property of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine at least two properties ofa specimen. The system may include a measurement device. In this manner,controlling the system may include controlling the measurement device.In addition, the measurement device may include an illumination systemand a detection system. The measurement device may also be coupled to astage. Controlling the measurement device may include controlling theillumination system to direct energy toward a surface of the specimen.Additionally, controlling the measurement device may include controllingthe detection system to detect energy propagating from the surface ofthe specimen. The method may also include generating one or more outputsignals in response to the detected energy. The computer-implementedmethod may further include processing the one or more output signals todetermine at least a first property and a second property of thespecimen. For example, the first property may include a concentration ofan element in the specimen. The second property may include a thicknessof the specimen. In addition, the processor may be configured todetermine other properties of the specimen from the one or more outputsignals.

An embodiment relates to a system coupled to a deposition tool. Thedeposition tool may be configured to form a layer of material on aspecimen. The layer of material may be formed on the specimen by thedeposition tool. The measurement device may be configured to determine acharacteristic of a layer of material prior to, during, or afterformation of the layer. The system may include a stage configured tosupport the specimen. The measurement device may include an illuminationsystem configured to direct energy toward a surface of the specimenprior to, during, or after formation of the layer. The measurementdevice may also include a detection system coupled to the illuminationsystem. The detection system may be configured to detect energypropagating from the surface of the specimen prior to, during, or afterformation of the layer. The measurement device may be configured togenerate one or more output signals in response to the detected energy.The system may also include a processor coupled to the measurementdevice. The processor may be configured to determine a characteristic ofthe layer from the one or more output signals. The processor may also becoupled to the deposition tool. The processor may be configured to altera parameter of one or more instruments coupled to the deposition tool.Additionally, the processor may be configured to alter a parameter ofthe instruments coupled to the deposition tool in response to thedetermined characteristic of the formed layer.

In an embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, or any combination thereof. In this manner, themeasurement device may be configured to function as a single measurementdevice or as multiple measurement devices. Because multiple measurementdevices may be integrated into a single measurement device of thesystem, optical elements of a first measurement device, for example, mayalso be optical elements of a second measurement device. The depositiontool may include any tool configured to form a layer upon asemiconductor substrate. Deposition tools may include chemical vapordeposition tools, physical vapor deposition tool, atomic layerdeposition tools, and electroplating tools.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or the deposition tool and a remotecontroller computer coupled to the local processor. The local processormay be configured to at least partially process the one or more outputsignals. The remote controller computer may be configured to receive theat least partially processed one or more output signals from theprocessor. In addition, the remote controller computer may be configuredto determine a characteristic of the formed layer on the specimen fromthe at least partially processed one or more output signals.Furthermore, the remote controller computer may be configured todetermine additional properties of the specimen from the at leastpartially processed one or more output signals. The remote controllercomputer may also be coupled to a deposition tool. In this manner, theremote controller computer may be further configured to alter aparameter of one or more instruments coupled to the deposition tool inresponse to at least the determined characteristic of a layer formedupon the specimen using an in situ control technique, a feedback controltechnique, and/or a feedforward control technique.

An additional embodiment relates to a method of evaluating acharacteristic of a layer formed upon a specimen. The method may includedepositing a layer upon a specimen using a deposition tool. Themeasurement device may include an illumination system and a detectionsystem. In addition, the method may include directing energy toward asurface of the specimen using the illumination system. The method mayalso include detecting energy propagating from the surface of thespecimen using the detection system. The method may further includegenerating one or more output signals in response to the detected light.Furthermore, the method may include processing the one or more outputsignals to determine a characteristic of the formed layer.

In an embodiment, the processor may be configured to determine acharacteristic of the formed layer. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an additional embodiment, a semiconductor devicemay be fabricated by the method. For example, the method may includeforming a portion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determinea characteristic of a formed layer may include at least partiallyprocessing the one or more output signals using a local processor. Thelocal processor may be coupled to the measurement device. Processing theone or more output signals may also include sending the partiallyprocessed one or more output signals from the local processor to aremote controller computer. In addition, processing the one or moreoutput signals may include further processing the partially processedone or more output signals using the remote controller computer. In anadditional embodiment, the remote controller computer may be coupled tothe deposition tool. In this manner, the method may include altering aparameter of one or more instruments coupled to the deposition toolusing the remote controller computer in response to at least thedetermined characteristic of the formed layer on the specimen. Alteringthe parameter of the deposition tool may include using an in situcontrol technique, a feedback control technique, and/or a feedforwardcontrol technique.

Additional embodiments relate to a computer-implemented method forcontrolling a system that includes a deposition tool and a measurementdevice. Controlling the system may include controlling the measurementdevice, the deposition tool, or both. In addition, the measurementdevice may include an illumination system and a detection system. Themeasurement device may also be coupled to a stage. Controlling themeasurement device may include controlling the illumination system todirect energy toward a surface of the specimen. Additionally,controlling the measurement device may include controlling the detectionsystem to detect energy propagating from the surface of the specimen.The method may also include generating one or more output signals inresponse to the detected energy. The computer-implemented method mayfurther include processing the one or more output signals to determineat least a characteristic of the layer as it is formed or after it isformed. In addition, the processor may be configured to determine otherproperties of the specimen from the one or more output signals.

An embodiment relates to a system that includes an etch tool coupled toa beam profile ellipsometer. The etch tool may be configured to directchemically reactive and/or ionic species toward a specimen. The beamprofile ellipsometer may be configured to determine a property of anetched region of the specimen during or after the etching process. Thebeam profile ellipsometer may include an illumination system configuredto direct an incident beam of light having a known polarization statetoward a surface of the specimen during or after etching of thespecimen. The measurement device may also include a detection systemcoupled to the illumination system. The detection system may beconfigured to generate one or more output signals representative oflight returned from the specimen during or after etching of thespecimen. The system may also include a processor coupled to themeasurement device. The processor may be configured to determine aproperty of the etched region of a specimen from the one or more outputsignals. The processor may also be coupled to the etch tool. Theprocessor may alter a parameter of one or more instruments coupled tothe etch tool. Additionally, the processor may be configured to alter aparameter of the instruments coupled to the etch tool in response to theproperties of the etched layer.

In an embodiment, the system may also include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field and/or dark field imagingdevice, a bright field and/or dark field non-imaging device, a coherenceprobe microscope, an interference microscope, or any combinationthereof. In this manner, the system may be configured to function as asingle measurement device or as multiple measurement devices. Becausemultiple measurement devices may be integrated into a single measurementdevice of the system, optical elements of a first measurement device,for example, may also be optical elements of a second measurementdevice.

In an embodiment, the processor may include a local processor coupled tothe beam profile ellipsometer and/or the etch tool and a remotecontroller computer coupled to the local processor. The local processormay be configured to at least partially process the one or more outputsignals. The remote controller computer may be configured to receive theat least partially processed one or more output signals from theprocessor. In addition, the remote controller computer may be configuredto determine a property of an etched region on the specimen from the atleast partially processed one or more output signals. Furthermore, theremote controller computer may be configured to determine additionalproperties of the specimen from the at least partially processed one ormore output signals. The remote controller computer may also be coupledto a etch tool. In this manner, the remote controller computer may befurther configured to alter a parameter of one or more instrumentscoupled to the etch tool in response to at least the determined propertyof the etched region of the specimen using an in situ control technique,a feedback control technique, and/or a feedforward control technique.

An additional embodiment relates to a method of evaluating an etchedregion of a specimen with a beam profile ellipsometer. The method mayinclude etching a layer upon a specimen using an etch tool. The beamprofile ellipsometer may include an illumination system and a detectionsystem. In addition, the method may include directing light toward asurface of the specimen using the illumination system. The method mayalso include detecting light propagating from the surface of thespecimen using the detection system. The method may further includegenerating one or more output signals in response to the detected light.Furthermore, the method may include processing the one or more outputsignals to a property of the etched region of the specimen. In addition,the method may include processing the one or more output signals todetermine other properties of the specimen from the one or more outputsignals. In an additional embodiment, a semiconductor device may befabricated by the method. For example, the method may include forming aportion of a semiconductor device upon a specimen such as asemiconductor substrate.

In an embodiment, processing the one or more output signals to determinea property of an etched region of a specimen may include at leastpartially processing the one or more output signals using a localprocessor. The local processor may be coupled to the beam profileellipsometer. Processing the one or more output signals may also includesending the partially processed one or more output signals from thelocal processor to a remote controller computer. In addition, processingthe one or more output signals may include further processing thepartially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to the etch tool. In this manner, the method mayinclude altering a parameter of one or more instruments coupled to theetch tool using the remote controller computer in response to at leastthe determined characteristic of the formed layer on the specimen.Altering the parameter of the etch tool may include using an in situcontrol technique, a feedback control technique, and/or a feedforwardcontrol technique.

Additional embodiments relate to a computer-implemented method forcontrolling a system that includes an etch tool and a beam profileellipsometer. Controlling the system may include controlling the beamprofile ellipsometer, the etch tool, or both. In addition, the beamprofile ellipsometer may include an illumination system and a detectionsystem. The beam profile ellipsometer may also be coupled to a stage.Controlling the beam profile ellipsometer may include controlling theillumination system to direct light toward a surface of the specimen.Additionally, controlling the beam profile ellipsometer may includecontrolling the detection system to detect light propagating from thesurface of the specimen. The method may also include generating one ormore output signals in response to the detected light. Thecomputer-implemented method may further include processing the one ormore output signals to determine at least a property of an etched regionof a specimen during etching, after the region is etched, or both. Inaddition, the processor may be configured to determine other propertiesof the specimen from the one or more output signals.

An embodiment relates to a system that includes an ion implanter coupledto a measurement device. The measurement device may be configured todetermine at least a characteristic of an implanted region of aspecimen. The measurement device may be configured to determine acharacteristic of an implanted region of a specimen during or afterimplantation of the specimen. The system may include a stage configuredto support the specimen. The measurement device may include anillumination system configured to periodically direct two or more beamsof light toward a surface of the specimen during or after implantation.In one embodiment, the measurement device may direct an incident beam oflight to a specimen to periodically excite a region of the specimenduring implantation. Additionally, the measurement device may direct asample beam of light to the excited region of the specimen. Themeasurement device may also include a detection system coupled to theillumination system. The detection system may be configured to measurean intensity of the sample beam reflected from the excited region of thespecimen. The measurement device may also be configured to generate oneor more output signals in response to the measured intensity.

The system may also include a processor coupled to the measurementdevice. The processor may be configured to determine a characteristic ofan implanted region from the one or more output signals. The processormay also be coupled to the ion implanter. The processor may beconfigured to alter a parameter coupled to one or more instrumentscoupled to the ion implanter. Additionally, the processor may beconfigured to alter a parameter of one or more instruments coupled tothe ion implanter in response to the determined characteristic of theimplanted region.

In an embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, a bright field and/or darkfield imaging device, a bright field and/or dark field non-imagingdevice, a coherence probe microscope, an interference microscope, anoptical profilometer, a modulated optical reflectance device, or anycombination thereof. In this manner, the measurement device may beconfigured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or the ion implanter and a remote controllercomputer coupled to the local processor. The local processor may beconfigured to at least partially process the one or more output signals.The remote controller computer may be configured to receive the at leastpartially processed one or more output signals from the processor. Inaddition, the remote controller computer may be configured to determinea characteristic of the implanted region of the specimen from the atleast partially processed one or more output signals. Furthermore, theremote controller computer may be configured to determine additionalproperties of the specimen from the at least partially processed one ormore output signals. The remote controller computer may also be coupledto an ion implanter. In this manner, the remote controller computer maybe further configured to alter a parameter of one or more instrumentscoupled to the ion implanter in response to at least the determinedproperty of the ion implantation region of the specimen using an in situcontrol technique, a feedback control technique, and/or a feedforwardcontrol technique.

An additional embodiment relates to a method of evaluating an implantedregion of a specimen. The method may include implanting ions into aregion of a specimen using an ion implanter. The measurement device mayinclude an illumination system and a detection system. In addition, themethod may include directing an incident beam of light toward a regionof the specimen to periodically excite the region of the specimen duringimplantation or after implantation. A sample beam may also be directedto the excited region of the specimen. The method may also includemeasuring an intensity of light propagating from the excited region ofthe specimen using the detection system. The method may further includegenerating one or more output signals in response to the measuredintensity. Furthermore, the method may include processing the one ormore output signals to determine a characteristic of the implantedregion. In addition, the method may include processing the one or moreoutput signals to determine other properties of the specimen from theone or more output signals. In an additional embodiment, a semiconductordevice may be fabricated by the method. For example, the method mayinclude forming a portion of a semiconductor device upon a specimen suchas a semiconductor substrate.

In an embodiment, processing the one or more output signals to determinea property of an ion implantation region may include at least partiallyprocessing the one or more output signals using a local processor. Thelocal processor may be coupled to the measurement device. Processing theone or more output signals may also include sending the partiallyprocessed one or more output signals from the local processor to aremote controller computer. In addition, processing the one or moreoutput signals may include further processing the partially processedone or more output signals using the remote controller computer. In anadditional embodiment, the remote controller computer may be coupled tothe ion implanter. In this manner, the method may include altering aparameter of one or more instruments coupled to the ion implanter usingthe remote controller computer in response to at least the determinedproperty of the ion implanted region of the specimen. Altering theparameter of the ion implanter may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system that includes an ion implanter and a measurementdevice. Controlling the system may include controlling the measurementdevice, the ion implanter, or both. In addition, the measurement devicemay include an illumination system and a detection system. Themeasurement device may also be coupled to a stage. Controlling themeasurement device may include controlling the illumination system todirect light toward a surface of the specimen. Additionally, controllingthe measurement device may include controlling the detection system todetect light propagating from the surface of the specimen. The methodmay also include generating one or more output signals in response tothe detected light. The computer-implemented method may further includeprocessing the one or more output signals to determine at least acharacteristic an implanted region of the specimen. In addition, themethod may include determining other properties of the specimen from theone or more output signals.

An embodiment relates to a system that includes a process chambercoupled to a measurement device. The process chamber may be configuredto fabricate a portion of a semiconductor device on a specimen. Themeasurement device may be configured to determine a presence of defectson a specimen. The measurement device may be configured to determine apresence of defects on a specimen prior to, during, or after fabricationof a portion of the semiconductor device on the specimen. In oneembodiment, the measurement device may be configured to detect microdefects. The system may include a stage configured to support thespecimen. The stage may be configured to rotate.

The measurement device may include an illumination system configured todirect energy toward a surface of the specimen prior to, during, orafter fabrication. Additionally, the measurement device may beconfigured to direct energy toward a surface of the specimen while thestage is stationary or while the stage is rotating. The measurementdevice may also include a detection system coupled to the illuminationsystem. The detection system may be configured to detect energypropagating from the surface of the specimen. The detection system maydetect energy prior to, during, or after fabrication. The detectionsystem may also be configured to detect energy while the stage isstationary or rotating. The measurement device may also be configured togenerate one or more output signals in response to the detected energy.

The system may also include a processor coupled to the measurementdevice. The processor may be configured to a presence of defects on asurface of the specimen from the one or more output signals. Theprocessor may also be coupled to the process chamber. The processor maycontrol a parameter of one or more instruments coupled to the processchamber. Additionally, the processor may be configured to alter aparameter of one or more instruments coupled to the process chamber inresponse to the detection of micro defects on the surface of thespecimen.

In an embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field and/or dark field imagingdevice, a bright field and/or dark field non-imaging device, a coherenceprobe microscope, an interference microscope, an optical profilometer,or any combination thereof. In this manner, the measurement device maybe configured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and/or the process chamber and a remotecontroller computer coupled to the local processor. The local processormay be configured to at least partially process the one or more outputsignals. The remote controller computer may be configured to receive theat least partially processed one or more output signals from the localprocessor. In addition, the remote controller computer may be configuredto determine a presence of defects on the specimen from the at leastpartially processed one or more output signals. Furthermore, the remotecontroller computer may be configured to determine additional propertiesof the specimen from the at least partially processed one or more outputsignals. The remote controller computer may also be coupled the processchamber. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process chamber in response to a determined presence of defects onthe specimen using an in situ control technique, a feedback controltechnique, and/or a feedforward control technique.

An additional embodiment relates to a method of evaluating a presence ofdefects on a surface of a specimen using a system that includes aprocess tool and a measurement device. The method may be used to detecta presence of micro defects on a specimen. The method may includefabricating a portion of a semiconductor device on a specimen using aprocess tool. The measurement device may include an illumination systemand a detection system. In addition, the method may include directingenergy toward a surface of the specimen. The method may also includedetecting energy propagating from the specimen using the detectionsystem. The method may further include generating one or more outputsignals in response to the detected energy. Furthermore, the method mayinclude processing the one or more output signals to determine apresence of defects on the specimen. The measurement device may beconfigured to determine the presence of defects prior to, during, orafter a process. The specimen may also be placed on a stage. The methodmay include determining a presence of defects on the specimen while thestage is stationary or a while the stage is rotating.

In addition, the method may include determining other properties of thespecimen from the one or more output signals. In an additionalembodiment, a semiconductor device may be fabricated by the method. Forexample, the method may include forming a portion of a semiconductordevice upon a specimen such as a semiconductor substrate.

In an embodiment, processing the one or more output signals to determinea presence of defects on a specimen may include at least partiallyprocessing the one or more output signals using a local processor. Thelocal processor may be coupled to the measurement device. Processing theone or more output signals may also include sending the partiallyprocessed one or more output signals from the local processor to aremote controller computer. In addition, processing the one or moreoutput signals may include further processing the partially processedone or more output signals using the remote controller computer. In anadditional embodiment, the remote controller computer may be coupled tothe process tool. In this manner, the method may include altering aparameter of one or more instruments coupled to the process tool usingthe remote controller computer in response to the one or more outputsignals. Altering the parameter of the process tool may include using anin situ control technique, a feedback control technique, and/or afeedforward control technique.

Additional embodiments relate to a computer-implemented method forcontrolling a system that includes a process tool and a measurementdevice. Controlling the system may include controlling the measurementdevice, the process tool, or both. In addition, the measurement devicemay include an illumination system and a detection system. Themeasurement device may also be coupled to a stage. Controlling themeasurement device may include controlling the illumination system todirect energy toward a surface of the specimen. Additionally,controlling the measurement device may include controlling the detectionsystem to detect energy propagating from the surface of the specimen.The method may also include generating one or more output signals inresponse to the detected energy. The computer-implemented method mayfurther include processing the one or more output signals to determine apresence of defects on the specimen prior to, during, or subsequent toprocessing. In addition, the processor may be configured to determineother properties of the specimen from the one or more output signals.

An embodiment relates to a system that may be configured to determine apresence of defects on multiple surfaces of a specimen. The system mayinclude a stage configured to support the specimen. The system may alsoinclude a measurement device coupled to the stage. The stage may beconfigured to move. The measurement device may include an illuminationsystem configured to direct energy toward a front side and a back sideof the specimen. The illumination system may be used while the stage isstationary or moving. The measurement device may also include adetection system coupled to the illumination system. The detectionsystem may be configured to detect energy propagating along multiplepaths from the front and back sides of the specimen. The system may alsoinclude a processor coupled to the measurement device. The measurementdevice may be configured to generate one or more output signals inresponse to the detected light. The processor may be configured todetermine a presence of defects on the front and back sides of thespecimen from the one or more output signals.

In addition, the processor may be configured to determine otherproperties of the specimen from the one or more output signals. In anembodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field and/or dark field imagingdevice, a bright field and/or dark field non-imaging device, a coherenceprobe microscope, an interference microscope, an optical profilometer,or any combination thereof. In this manner, the measurement device maybe configured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device.

In an embodiment, the processor may include a local processor coupled tothe measurement device and a remote controller computer coupled to thelocal processor. The local processor may be configured to at leastpartially process the one or more output signals. The remote controllercomputer may be configured to receive the at least partially processedone or more output signals from the processor. In addition, the remotecontroller computer may be configured to determine a presence of defectson the front and back sides of the specimen from the at least partiallyprocessed one or more output signals. Furthermore, the remote controllercomputer may be configured to determine additional properties of thespecimen from the at least partially processed one or more outputsignals. In an additional embodiment, the remote controller computer maybe coupled to a process tool such as a semiconductor fabrication processtool. In this manner, the remote controller computer may be furtherconfigured to alter a parameter of one or more instruments coupled tothe process tool in response to at least the determined first or secondproperty of the specimen using an in situ control technique, a feedbackcontrol technique, and/or a feedforward control technique.

An additional embodiment relates to a method for determining defects onmultiple surfaces of a specimen. The method may include disposing aspecimen upon a stage. The stage may be coupled to a measurement device.The measurement device may include an illumination system and adetection system. In addition, the method may include directing energytoward a front side and a back side of the specimen using theillumination system. The method may also include detecting energypropagating along multiple paths from the front and back sides of thespecimen using the detection system. The method may further includegenerating one or more output signals in response to the detectedenergy. Furthermore, the method may include processing the one or moreoutput signals to determine the presence of defects on the front andback sides of the specimen.

In addition, the processor may be configured to determine otherproperties of the specimen from the one or more output signals. In anadditional embodiment, a semiconductor device may be fabricated by themethod. For example, the method may include forming a portion of asemiconductor device upon a specimen such as a semiconductor substrate.

In an embodiment, processing the one or more output signals to determinethe presence of defects on multiple surfaces of the specimen may includeat least partially processing the one or more output signals using alocal processor. The local processor may be coupled to the measurementdevice. Processing the one or more output signals may also includesending the partially processed one or more output signals from thelocal processor to a remote controller computer. In addition, processingthe one or more output signals may include further processing thepartially processed one or more output signals using the remotecontroller computer. In an additional embodiment, the remote controllercomputer may be coupled to a process tool such as a semiconductorfabrication process tool. In this manner, the method may includealtering a parameter of one or more instruments coupled to the processtool using the remote controller computer in response to a determinedpresence of defects on multiple surfaces of the specimen. Altering theparameter of the instruments may include using an in situ controltechnique, a feedback control technique, and/or a feedforward controltechnique.

Additional embodiments relate to a computer-implemented method forcontrolling a system configured to determine defects on multiplesurfaces of a specimen. The system may include a measurement device. Inthis manner, controlling the system may include controlling themeasurement device. In addition, the measurement device may include anillumination system and a detection system. The measurement device mayalso be coupled to a stage. Controlling the measurement device mayinclude controlling the illumination system to direct energy toward asurface of the specimen. Additionally, controlling the measurementdevice may include controlling the detection system to detect energypropagating from the surface of the specimen. The stage may beconfigured to move. The method may also include controlling the stagesuch that the specimen is moved during analysis. The method may furtherinclude generating one or more output signals in response to thedetected energy. The computer-implemented method may further includeprocessing the one or more output signals to determine a presence ofdefects on multiple surfaces of the specimen.

In an embodiment, any of the systems, as described herein, may be usedduring the production of a semiconductor device. A semiconductor devicemay be formed using one or more semiconductor processing steps. Eachprocessing step may cause a change to a specimen. After a processingstep, a portion of the semiconductor device may be formed upon aspecimen. Prior to, during, or subsequent to a processing step, thespecimen may be placed on a stage of a system configured to determine atleast two properties of the specimen. The system may be configuredaccording to any of the above embodiments.

After the first and second properties are determined, these propertiesmay be used to determine further processing steps for formation of thesemiconductor device. For example, the system may be used to evaluate ifa semiconductor process is performing adequately. If a semiconductorprocess is not performing adequately, data obtained from the system maybe used to determine further processing the specimen. In anotherembodiment, detection of an incorrectly processed specimen may indicatethat the specimen should be removed from the semiconductor process. Byusing a multiple analysis system such as described above, processing ofsemiconductor devices may be enhanced. The time required for testing maybe reduced. Also, the use of multiple tests may ensure that onlyapparently properly processed specimens are advanced to the nextprocessing steps. In this manner, yield of semiconductor devices mayincrease.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to theaccompanying drawings in which:

FIG. 1 depicts a schematic top view of an embodiment of a specimenhaving a plurality of dies and a plurality of defects on a surface of aspecimen;

FIG. 2 a depicts a schematic top view of an embodiment of a stageconfigured to move rotatably during use and a measurement deviceconfigured to move linearly during use;

FIG. 2 b depicts a schematic top view of an embodiment of a stageconfigured to move rotatably during use and a stationary measurementdevice;

FIG. 3 depicts a schematic side view of an embodiment of a system havingone illumination system and one detection system;

FIG. 4 depicts a schematic side view of an embodiment of a system havingmultiple illumination systems and one detection system;

FIG. 5 depicts a schematic side view of an embodiment of a system havingmultiple illumination systems and multiple detection system;

FIG. 6 depicts a schematic side view of an embodiment of a system havingone illumination system and multiple detection systems;

FIG. 7 depicts a schematic side view of an embodiment of a system havingone illumination system and multiple detection systems;

FIG. 8 depicts a schematic side view of an embodiment of a specimen;

FIG. 9 depicts a schematic top view of an embodiment of a system havinga plurality of measurement devices;

FIG. 10 depicts a schematic side view of an embodiment of a systemconfigured to determine a critical dimension of a specimen;

FIG. 11 a depicts a schematic side view of an embodiment of ameasurement device configured to determine a critical dimension of aspecimen;

FIG. 11 b depicts a schematic side view of an embodiment of a portion ofa measurement device configured to determine a critical dimension of aspecimen;

FIG. 12 depicts a schematic side view of an embodiment of a systemconfigured to determine multiple properties of multiple surfaces of aspecimen;

FIG. 13 depicts a schematic top view of an embodiment of a systemcoupled to a semiconductor fabrication process tool;

FIG. 14 depicts a perspective view of an embodiment of a systemconfigured to be coupled to a semiconductor fabrication process tool;

FIG. 15 depicts a perspective view of an embodiment of a system coupledto a semiconductor fabrication process tool;

FIG. 16 depicts a schematic side view of an embodiment of a systemdisposed within a measurement chamber;

FIG. 17 depicts a schematic side view of an embodiment of a measurementchamber arranged laterally proximate to a process chamber of asemiconductor fabrication process tool;

FIG. 18 depicts a schematic side view of an embodiment of a systemcoupled to a process chamber of a semiconductor fabrication processtool;

FIG. 19 depicts a flow chart illustrating an embodiment of a method fordetermining at least two properties of a specimen;

FIG. 20 depicts a flow chart illustrating an embodiment of a method forprocessing detected light returned from a surface of the specimen;

FIG. 21 depicts a flow chart illustrating an embodiment of a method forcontrolling a system configured to determine at least two properties ofa specimen;

FIG. 22 depicts a schematic side view of an embodiment of a systemcoupled to a chemical-mechanical polishing tool;

FIG. 23 depicts a schematic side view of an embodiment of a systemcoupled to a chemical vapor deposition tool;

FIG. 24 depicts a schematic side view of an embodiment of a systemcoupled to an etch tool;

FIG. 25 depicts a schematic side view of an embodiment of a systemcoupled to an ion implanter;

FIG. 26 depicts a schematic side view of an embodiment of a systemconfigured to determine a characteristic of micro defects on a surfaceof a specimen; and

FIG. 27 depicts a schematic side view of an embodiment of a systemconfigured to determine a characteristic of defects of multiple surfacesof a specimen.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, FIG. 1 illustrates a schematic top view ofan embodiment of a surface of specimen 10. Specimen 10 may include asubstrate such as a monocrystalline silicon substrate, a silicongermanium substrate, or a gallium arsenide substrate. In addition,specimen 10 may include any substrate suitable for fabrication ofsemiconductor devices. Specimen 10 may include plurality of dies 12having repeatable pattern features. Alternatively, specimen 10 may beunpatterned such as a virgin semiconductor wafer or an unprocessedwafer. In addition, specimen 10 may include a glass substrate or anysubstrate formed from a substantially transparent material, which may besuitable for fabrication of a reticle. Furthermore, specimen 10 mayinclude any specimen known in the art.

In addition, specimen 10 may include one or more layers arranged upon asubstrate. For example, layers which may be formed on a substrate mayinclude, but are not limited to, a resist, a dielectric material, and/ora conductive material. The resist may include photoresist materials thatmay be patterned by an optical lithography technique. The resist mayinclude other resists, however, such as e-beam resists or X-ray resiststhat may be patterned by an e-beam or an X-ray lithography technique,respectively. Examples of an appropriate dielectric material mayinclude, but are not limited to, silicon dioxide, silicon nitride,silicon oxynitride, and titanium nitride. In addition, examples of anappropriate conductive material may include aluminum, polysilicon, andcopper. Furthermore, a specimen may also include semiconductor devicessuch as transistors formed on a substrate such as a wafer.

FIGS. 2 a and 2 b illustrate a schematic top view of an embodiment ofstage 24 configured to support a specimen. The stage may be a vacuumchuck or an electrostatic chuck. In this manner, a specimen may be heldsecurely in place on the stage. In addition, the stage may be amotorized translation stage, a robotic wafer handler, or any othersuitable mechanical device known in the art. In an embodiment, thesystem may include measurement device 26 coupled to the stage. As such,the stage may be configured to impart relative motion to the specimenwith respect to the measurement device. In an example, the stage may beconfigured to move the specimen relative to the measurement device in alinear direction. The relative motion of the stage may cause an incidentbeam of energy from an energy source of a measurement device to traversethe surface of the specimen while leaving the angle of incidence atwhich light strikes the surface of the specimen substantially unchanged.As used herein, the term “measurement device” is generally used to referto a metrology device, an inspection device, or a combination metrologyand inspection device.

As shown in FIGS. 2 a and 2 b, stage 24 may be configured to rotate inclockwise and counterclockwise directions as indicated by vector 28 suchthat a specimen may be oriented with respect to measurement device 26 ina plurality of directions. As such, the stage may also be used tocorrect an orientation of a specimen such that a specimen may besubstantially aligned with respect to a measurement device duringmeasurement or inspection. In addition, stage 24 may be furtherconfigured to rotate and to move linearly simultaneously. Examples ofmethods for aligning a specimen to a measurement device are illustratedin U.S. Pat. No. 5,682,242 to Eylon, U.S. Pat. No. 5,867,590 to Eylon,and U.S. Pat. No. 6,038,029 to Finarov, and are incorporated byreference as if fully set forth herein.

In an embodiment, stage 24 may be further configured to move along az-axis to alter a distance between a specimen and measurement device 26.For example, altering a distance between a specimen and a measurementdevice may substantially focus a beam of energy from an energy source ofthe measurement device on the surface of the specimen. Examples offocusing systems are illustrated in U.S. Pat. No. 5,604,344 to Finarov,and U.S. Pat. No. 6,124,924 to Feldman et al., which are incorporated byreference as if fully set forth herein. An example for focusing acharged particle beam on a specimen is illustrated in European PatentApplication No. EP 1 081 741 A2 to Pearl et al., and is incorporated byreference as if fully set forth herein.

As shown in FIG. 2 a, stage 24 may be configured to move with respect tomeasurement device 26, and the measurement device may be configured tomove with respect to the stage. For example, measurement device 26 maybe configured to move linearly along a direction indicated by vector 29while stage 24 may be configured to move rotatably. As such, an incidentbeam of energy from an energy source of the measurement device maytraverse a radius of the stage as the stage is rotating.

As shown in FIG. 2 b, measurement device 30 may be configured to berelatively stationary in a position relative to stage 24. Devices (notshown) including, but not limited to, a deflector such as anacousto-optical deflector (“AOD”) within measurement device 30 may beconfigured to linearly alter a position of an incident beam with respectto the stage. An example of an AOD is illustrated in PCT Application No.WO 01/14925 A1 to Allen et al., and is incorporated by reference as iffully set forth herein. In this manner, the incident beam may traverse aradius of the stage as the stage is rotating. In addition, by altering aposition of an incident beam with respect to the stage using suchdevices, registry of the measurement device with a pattern formed on asurface of a specimen may be maintained. The device may be configured tocause an incident beam of energy from an energy source of themeasurement device to traverse the surface of the specimen while leavingthe angle of incidence at which the beam of energy strikes the surfaceof the specimen substantially unchanged.

In a further embodiment, measurement device 30 may include a pluralityof energy sources such as illumination systems and a plurality ofdetection systems. The plurality of illumination systems and theplurality of detection systems may be arranged in two linear arrays. Theillumination systems and the detection systems may be arranged such thateach illumination system may be coupled to one of the detection systems.As such, measurement device 30 may be configured as a linear imagingdevice. In this manner, the measurement device may be configured tomeasure or inspect any location on a surface of specimen substantiallysimultaneously or sequentially. In addition, the measurement device maybe configured such that measurements may be made at multiple locationson a specimen substantially simultaneously while the stage may berotating. Furthermore, the stage and the measurement device may beconfigured to move substantially continuously or intermittently. Forexample, the stage and the measurement device may be movedintermittently such that the system may be configured as amove-acquire-measure system.

A measurement device and stage configured, as described above, tocontrol and alter the measurement or inspection location of the specimenmay provide several advantages in comparison to currently used systems.For example, currently used systems configured to inspect multiplelocations on a specimen may include a stationary measurement device anda stage configured to move laterally in two independent directions.Alternatively, currently used systems may include a stationary stage anda measurement device configured to alter a position of a beam of energyincident on a specimen by altering a position of two mirrors in a firstdirection and a position of two mirrors in a second direction. Anexample of such a system is illustrated in U.S. Pat. No. 5,517,312 toFinarov and U.S. Pat. No. 5,764,365 to Finarov, and are incorporated byreference as if fully set forth herein. An additional system may includea stage configured to rotate and a laser light source configured to moveradially. Such a system may be unsuitable for measurement or inspectinga patterned specimen. Additional examples of currently used systems areillustrated in U.S. Pat. No. 5,943,122 to Holmes, and is incorporated byreference as if fully set forth herein.

As the lateral dimension of specimens such as wafers increases to 300mm, moving a specimen linearly during inspection or measurement maybecome impractical due to space requirements of a typical semiconductorfabrication facility. In addition, moving such a specimen may becomeextremely expensive due to the cost of maintaining a relatively largerclean space for such tools. As such, a system configured as described inabove embodiments may be configured to inspect or measure an entiresurface of a specimen without linearly moving the specimen.

FIG. 3 illustrates a schematic side view of an embodiment of system 32configured to determine at least two properties of a specimen. System 32may include measurement device 34 having illumination system 36 anddetection system 38. Illumination system 36 may be configured to directlight toward a surface of specimen 40 disposed upon stage 42. Stage 42may be configured as described in above embodiments. Detection system 38may be coupled to illumination system 36 and may be configured to detectlight propagating from the surface of the specimen. For example,detection system 38, illumination system 36, and additional opticalcomponents may be arranged such that spectrally reflected light orscattered light propagating from the surface of specimen 40 may bedetected by the detection system.

Illumination system 36 may include energy source 44. Energy source 44may be configured to emit monochromatic light. For example, a suitablemonochromatic light source may be a gas laser or a solid state laserdiode. Alternatively, the energy source may be configured to emitelectromagnetic radiation of multiple wavelengths, which may includeultraviolet light, visible light, infra-red light, X-rays, gamma rays,microwaves, or radio-frequencies. In addition, the energy source may beconfigured to emit another source of energy source such as an beam ofelectrons, protons, neutrons, ion, or molecules. For example, a thermalfield emission source is typically used as an electron source.

Detection system 38 may include detector 46. Detector 46 may includelight sensitive sensor devices including, but not limited to, aphotodetector, a multi-cell photodetector, an interferometer, an arrayof photodiodes such as a linear sensor array, a conventionalspectrophotometer, a position sensitive detector, photomultiplier tubes,avalanche photodiodes, a charge-coupled device (“CCD”) camera, a timedelay integration (“TDI”) camera, a video camera, a pattern recognitiondevice, and an imaging system. In addition, the detector may includesolid state detectors such as Schottky solid state barrier detectors.

In addition, measurement device 34 may include any number of additionaloptical components (not shown). Appropriate optical components mayinclude, but are not limited to, beam splitters or dichroic mirrors,quarter wave plates, polarizers such as linear and circular polarizers,rotating polarizers, rotating analyzers, collimators, focusing lenses,additional lenses, folding mirrors, partially transmissive mirrors,filters such as spectral or polarizing filter, spatial filters,reflectors, deflectors, and modulators. Each of the additional opticalcomponents may be coupled to or disposed within the illumination systemor the detection system. Furthermore, the measurement device may includea number of additional electromagnetic devices (not shown) that mayinclude magnetic condenser lenses, magnetic objective lenses,electrostatic deflection systems, beam limiting apertures, and Wienfilters.

An arrangement of the illumination system, the detection system, andadditional optical and electromagnetic components may vary depending on,for example, the technique or techniques used to determine at least thetwo properties of the specimen. The arrangement of the illuminationsystem, the detection system, and additional optical and electromagneticcomponents may also depend on the properties of the specimen, which arebeing determined. For example, as shown in FIG. 3, measurement device 34may include optical component 48 disposed within or coupled toillumination system 36. Optical component 48 may include, but is notlimited to, a polarizer, a spectral or polarizing filter, and a quarterwave plate. In addition, measurement device 34 may include beam splitter50 and optical component 52. Optical component 52 may be disposed withinor coupled to detection system 38. Optical component 52 may include, butis not limited to, a quarter wave plate, a collimator, and a focusinglens.

FIGS. 4-7 illustrate alternate embodiments of measurement device 34 ofsystem 32. As will be further described herein, elements of system 32,which may be similarly configured in each of the embodiments illustratedin FIGS. 3-7 have been indicated by the same reference characters. Forexample, energy source 44 may be similarly configured in each of theembodiments illustrated in FIGS. 3-7. As shown in FIG. 4, measurementdevice 34 may include a plurality of energy sources 44. Each of energysources may be configured to emit substantially similar types of energyor different types of energy. For example, the plurality of energysources 44 may include any of the light sources described herein. Thelight sources may be configured to emit broadband light. Alternatively,the light sources may include two emit different types of light. Forexample, one of the light sources may be configured to emit light of asingle wavelength, and the other light source may be configured to emitbroadband light. In addition, the energy sources may be configured todirect a beam of energy to substantially the same location on thesurface of specimen 40, as shown in FIG. 4. Alternatively, the pluralityof energy sources 44 may be configured to direct a beam of energy tosubstantially different locations on the surface of specimen 40, asshown in FIG. 5. For example, as shown in FIG. 5, the plurality ofenergy sources may be configured to direct energy to laterally spacedlocations on the surface of specimen 40. The plurality of energy sourcesshown in FIG. 5 may also be configured as described above.

As shown in FIG. 4, measurement device may include detector 46 coupledto the plurality of energy sources 44. In this manner, detector 46 maybe positioned with respect to the plurality of energy sources such thatthe detector may be configured to detect different types of energypropagating from the surface of specimen 40 such as specularly reflectedlight and scattered light. The detector may also be configured to detectdifferent types of energy propagating from the surface of the specimensubstantially simultaneously. For example, the detector may include anarray of photodiodes. A first portion of the array of photodiodes may beconfigured to detect only incident light from one of the plurality oflight sources propagating from the surface of the specimen. A secondportion of the array of photodiodes may be configured to detect onlyincident light from the other of the plurality of light sourcepropagating from the surface of the specimen. As such, the detector maybe configured to detect incident light from each of a plurality of lightsources propagating from the surface of the specimen substantiallysimultaneously. Alternatively, the plurality of energy sources may beconfigured to intermittently direct energy to the surface of thespecimen. As such, the detector may be configured to detect incidentenergy from each of the plurality of energy sources propagating from thesurface of the specimen intermittently.

As shown in FIG. 5, measurement device 34 may include a plurality ofdetectors 46. Each of the plurality of detectors may be coupled to oneof the plurality of energy sources 44. In this manner, each detector 46may be positioned with respect to one of the energy sources such thatthe detector may be configured to detect incident energy from one of theenergy sources propagating from the surface of specimen 40. For example,one of the detectors may be positioned with respect to a first lightsource to detect light scattered from the surface of the specimen. In anexample, scattered light may include dark field light propagating alonga dark field path. A second of the plurality of detectors may bepositioned with respect to a second light source to detect lightspecularly reflected from the surface of the specimen such as brightfield light propagating along a bright field path. The plurality ofdetectors may be configured as described in above embodiments. Forexample, the plurality of detectors may include two different detectorsor two of the same type of detectors. For example, a first detector maybe configured as a conventional spectrophotometer, and a second detectormay be configured as a quad-cell detector. Alternatively, both detectorsmay be configured as an array of photodiodes.

As shown in FIG. 4, measurement device 34 may also include multipleoptical components 48. For example, optical components 48 may be coupledto each of the plurality of energy sources 44. In an example, a first ofthe optical components may be configured as a polarizer, and a second ofthe optical components may be configured as a focusing lens.Alternatively, as shown in FIG. 5, measurement device 34 may include oneoptical component 48 coupled to each of the plurality of energy sources44. Each of the optical components 48 may be configured as describedherein. In addition, as shown in FIG. 5, measurement device 34 mayinclude an optical component such as beam splitter 50 coupled to one ofthe plurality of energy sources. For example, beam splitter 50 may bepositioned along a path of light directed from a light source. Beamsplitter 50 may be configured to transmit light from the light sourceand to reflect light propagating from the surface of the specimen. Thebeam splitter may be configured to reflect light propagating from thesurface of the specimen such that the reflected light may be directed todetector 46. In addition, beam splitters may be positioned along a pathof the light directed from each of the plurality of light sources.Optical component 52 may also be coupled to detector 46, as shown inFIG. 4, and may be configured as, for example, a quarter wave plate, acollimator, and a focusing lens. Optical component 52 may be furtherconfigured as described herein. Multiple optical components 52 may alsobe coupled to each of the detectors. The position and the configurationof each of the optical components may vary, however, depending on theproperties of the specimen to be determined by the system as will bedescribed in more detail below.

FIGS. 6 and 7 illustrate schematic side views of additional embodimentsof system 32. As shown in these figures, measurement device 34 mayinclude a single energy source 44. In addition, measurement device 34may include a plurality of detectors 46. The detectors may include anyof devices as described herein. Each of the plurality of detectors 46may be positioned at a different angle with respect to energy source 44.For example, as shown in FIG. 6, one of the detectors may be configuredto detect dark field light propagating along a dark field path. Thesecond detector may be configured to detect bright field lightpropagating along a bright field path. Alternatively, as shown in FIG.7, each of the plurality of detectors may be configured to detectspecularly reflected light. The plurality of detectors may be similarlyconfigured, for example, as photodiode arrays. Alternatively, theplurality of detectors may be configured as different detectors such asa conventional spectrophotometer and a quad cell detector.

In addition, the illumination system may be configured to directdifferent types of energy to the surface of the specimen at varyingintervals. For example, the energy source may be configured to emit onetype of light. As shown in FIG. 7, optical component 48 may be coupledto energy source 44. Optical component 48 may also be configured toalter the light emitted by energy source 44 at varying intervals. Forexample, optical component 48 may be configured as a plurality ofspectral and/or polarizing filters that may be rotated in a path of thelight emitted by energy source 44 at varying intervals or a liquidcrystal display (“LCD”) filter that may be controlled by a controllercoupled to the filter. The controller may be configured to alter thetransmissive, reflective, and/or polarization properties of the LCDfilter at varying intervals. The properties of the LCD filter may bealtered to change a spectral property or a polarization state of thelight emitted from the energy source. In addition, each of the pluralityof detectors may be suitable to detect a different type of lightpropagating from the surface of the specimen. As such, the measurementdevice may be configured to measure substantially different opticalcharacteristics of the specimen at varying intervals. In this manner,measurement device 34 may be configured such that energy directed to thesurface of the specimen and the energy returned from the surface of thespecimen may vary depending on, for example, the properties of thespecimen to be measured using the system.

In an embodiment, system 32, as shown in FIGS. 3-7, may includeprocessor 54 coupled to measurement device 34. The processor may beconfigured to receive one or more output signals generated by a detectorof the measurement device. The one or more output signals may berepresentative of the detected energy returned from the specimen. Theone or more output signals may be an analog signal or a digital signal.The processor may be configured to determine at least a first propertyand a second property of the specimen from the one or more outputsignals generated by the detector. The first property may include acritical dimension of specimen 40, and the second property may includeoverlay misregistration of specimen 40. For example, the measurementdevice may include, but is not limited to, a scatterometer, anon-imaging scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a beam profile ellipsometer, a bright fieldimaging device, a dark field imaging device, a bright field and darkfield imaging device, a bright field non-imaging device, a dark fieldnon-imaging device, a bright field and dark field non-imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, or any combination thereof. In this manner, the system maybe configured as a single measurement device or as multiple measurementdevices.

Because multiple measurement devices may be integrated into a singlesystem, optical elements of a first measurement device, for example, mayalso be used as optical elements of a second measurement device. Inaddition, multiple measurement devices may be coupled to a common stage,a common handler, and a common processor. The handler may include amechanical device configured to dispose a specimen on the common stageand to remove a specimen from the common stage or any other handler asdescribed herein. In addition, the system may be configured to determinea critical dimension and an overlay misregistration of a specimensequentially or substantially simultaneously. In this manner, such asystem may be more cost, time, and space efficient than systemscurrently used in the semiconductor industry.

FIG. 8 illustrates a schematic side view of an embodiment of a specimen.As shown in FIG. 8, a plurality of features 56 may be formed upon uppersurface 58 of specimen 60. For example, features formed on an uppersurface of the specimen may include local interconnects, gate structuressuch as gate electrodes and dielectric sidewall spacers, contact holes,and vias. The plurality of features, however, may also be formed withinthe specimen. Features formed within the specimen may include, forexample, isolation structures such as field oxide regions within asemiconductor substrate and trenches. A critical dimension may include alateral dimension of a feature defined in a direction substantiallyparallel to an upper surface of the specimen such as width 62 of feature56 on specimen 60. Therefore, a critical dimension may be generallydefined as the lateral dimension of a feature when viewed in crosssection such as a width of a gate or interconnect or a diameter of ahole or via. A critical dimension of a feature may also include alateral dimension of a feature defined in a direction substantiallyperpendicular to an upper surface of the specimen such as height 64 offeature 56 on specimen 60.

In addition, a critical dimension may also include a sidewall angle of afeature. A “sidewall angle” may be generally defined as an angle of aside (or lateral) surface of a feature with respect to an upper surfaceof the specimen. In this manner, a feature having a substantiallyuniform width across a height of the feature may have sidewall angle 66of approximately 90°. Features of a specimen such as a semiconductordevice that have a substantially uniform width across a height of thefeatures may be formed relatively closely together thereby increasingdevice density of the semiconductor device. In addition, such a devicemay have relatively predictable and substantially uniform electricalproperties. A feature having a tapered profile or non-uniform widthacross a height of the feature may have sidewall angle 68 of less thanapproximately 90°. A tapered profile may be desired if a layer may beformed upon the feature. For example, a tapered profile may reduce theformation of voids within the layer formed upon the feature.

Overlay misregistration may be generally defined as a measure of thedisplacement of a lateral position of a feature on a first level of aspecimen with respect to a lateral position of a feature on a secondlevel of a specimen. The first level may be formed above the secondlevel. For example, overlay misregistration may be representative of thealignment of features on multiple levels of a semiconductor device.Ideally, overlay misregistration is approximately zero such thatfeatures on a first level of a specimen may be perfectly aligned tofeatures on a second level of a specimen. For example, a significantoverlay misregistration may cause undesirable contact of electricalfeatures on first and second levels of a specimen. In this manner, asemiconductor device formed on such a significantly misaligned specimenmay have a number of open or short circuits thereby causing devicefailure.

An extent of overlay misregistration of a specimen may vary dependingon, for example, performance characteristics of a lithography process.During lithography, a reticle, or a mask, may be disposed above a resistarranged on a first level of the specimen. The reticle may havesubstantially transparent regions and substantially opaque regions thatmay be configured in a pattern, which may be transferred to the resist.The reticle may be positioned above a specimen by an exposure toolconfigured to detect a position of an alignment mark on the specimen. Inthis manner, overlay misregistration may be caused by performancelimitations of an exposure tool to detect an alignment mark and to altera position of the reticle with respect to the specimen.

FIG. 9 illustrates a schematic top view of an embodiment of system 70having a plurality of measurement devices. Each of the measurementdevices may be configured as described herein. For example, each of themeasurement devices may be configured to determine at least one propertyof a specimen. In addition, each of the measurement devices may beconfigured to determine a different property of a specimen. As such,system 70 may be configured to determine at least four properties of aspecimen. For example, measurement device 72 may be configured todetermine a critical dimension of a specimen. In addition, measurementdevice 74 may be configured to determine overlay misregistration of thespecimen in a first lateral direction. Measurement device 76 may beconfigured to determine overlay misregistration of the specimen in asecond lateral direction. The first lateral direction may besubstantially orthogonal to the second lateral direction. Furthermore,measurement device 78 may be configured as a pattern recognition device.As such, system 70 may be configured to determine at least fourproperties of the specimen simultaneously or sequentially. In addition,each of the measurement devices may be configured to determine anyproperty of a specimen as described herein.

FIG. 10 illustrates a schematic side view of an embodiment of system 80configured to determine at least two properties of a specimen. Forexample, system 80 may be configured to determine at least a criticaldimension of a specimen. As such, system 80 may be included in system 70as described in above embodiments. System 80 may include broadband lightsource 82. The term “broadband light” is generally used to refer toradiation having a frequency-amplitude spectrum that includes two ormore different frequency components. A broadband frequency-amplitudespectrum may include a broad range of wavelengths such as fromapproximately 190 nm to approximately 1700 nm. The range of wavelengths,however, may be larger or smaller depending on, for example, the lightsource capability, the sample being illuminated, and the property beingdetermined. For example, a xenon arc lamp may be used as a broadbandlight source and may be configured to emit a light beam includingvisible and ultraviolet light.

System 80 may also include beam splitter 84 configured to direct lightemitted from light source 82 to a surface of a specimen 85. The beamsplitter may be configured as a beam splitter mirror that may beconfigured to produce a continuous broadband spectrum of light. System80 may also include lens 86 configured to focus light propagating frombeam splitter 84 onto a surface of specimen 85. Light returned from thesurface of specimen 85 may pass through beam splitter 84 to diffractiongrating 88.

The diffraction grating may be configured to disperse light returnedfrom the surface of the specimen. The dispersed light may be directed toa spectrometer such as detector array 90. The detector array may includea linear photodiode array. The light may be dispersed by a diffractiongrating as it enters the spectrometer such that the resulting firstorder diffraction beam of the sample beam may be collected by the linearphotodiode array. Examples of spectroscopic reflectometers areillustrated in U.S. Pat. No. 4,999,014 to Gold et al., and U.S. Pat. No.5,747,813 to Norton et al. and are incorporated by reference as if fullyset forth herein.

The photodiode array, therefore, may measure the reflectance spectrum 92of the light returned from the surface of the specimen. A relativereflectance spectrum may be obtained by dividing the intensity of thereturned light of the reflectance spectrum at each wavelength by arelative reference intensity at each wavelength. A relative reflectancespectrum may be used to determine the thickness of various films on thewafer. In addition, the reflectance at a single wavelength and therefractive index of the film may also be determined from the relativereflectance spectrum. Furthermore, a model method by modal expansion(“MMME”) model 94 may be used to generate library 96 of variousreflectance spectrums. The MMME model is a rigorous diffraction modelthat may be used to calculate the theoretical diffracted light“fingerprint” from each grating in the parameter space. Alternativemodels may also be used to calculate the theoretical diffracted light,however, including, but not limited to, a rigorous coupling waveguideanalysis (“RCWA”) model. The measured reflectance spectrum 92 may befitted to the various reflectance spectrums in library 96. The fitteddata 97 may be used to determine critical dimension 95 such as a lateraldimension, a height, and a sidewall angle of a feature on the surface ofa specimen as described herein. Examples of modeling techniques areillustrated in PCT Application No. WO 99/45340 to Xu et al., and isincorporated by reference as if fully set forth herein.

FIGS. 11 a and 11 b illustrate additional schematic side views of anembodiment of measurement device 98 configured to determine a propertysuch as a critical dimension of a specimen. The measurement device maybe coupled to system 80 described above. Measurement device 98 mayinclude fiber optic light source 100. The fiber optic light source maybe configured to emit and direct light to collimating mirror 102.Collimating mirror 102 may be configured to alter a path of the lightemitted by the fiber optic light source such that it propagates toward asurface of specimen 104 in substantially one direction along path 106.Light emitted by fiber optic light source 100 may also be directed toreflective mirror 108. Reflective mirror 108 may be configured to directthe light emitted by the fiber optic light source to referencespectrometer 110. Reference spectrometer 110 may be configured tomeasure an intensity of light emitted by the fiber optic light source.In addition, reference spectrometer 110 may be configured to generateone or more output signals in response to the measured intensity oflight. As such, the signal generated by reference spectrometer 110 maybe used to monitor variations in the intensity of light emitted by thefiber optic light source.

Measurement device 98 may also include polarizer 112. Polarizer 112 maybe oriented at a 45° angle with respect to path 106 of the light.Polarizer 112 may be configured to alter a polarization state of thelight such that light propagating toward a surface of the specimen maybe linearly or circularly polarized. Measurement device 98 may alsoinclude light piston 114 positioned along path 106 of the light. Thelight piston may be configured to alter a direction of the path of thelight propagating toward the surface of the specimen. For example,portion 115 of the measurement device may be configured to move withrespect to the specimen to measure multiple locations on the specimen.In this manner, the light position may be configured to cause lightpropagating along path 106 to traverse the surface of the specimen whileleaving the angle of incidence at which light strikes the surface of thespecimen substantially unchanged.

The measurement device may also include apodizer 116. Apodizer 116 mayhave a two dimensional pattern of alternating relatively hightransmittance areas and substantially opaque areas. The alternatingpattern may have a locally averaged transmittance function such as anapodizing function. As such, an apodizer may be configured to reduce alateral area of an illuminated region of a specimen to improve afocusing resolution of the measurement device. The measurement devicemay also include a plurality of mirrors 118 configured to direct lightpropagating along path 106 to a surface of a specimen. In addition, themeasurement device may also include reflecting objective lens 120configured to direct the light to the surface of the specimen. Forexample, a suitable reflecting objective may have a numerical aperture(“NA”) of approximately 0.1 such that light may be may be directed at asurface of the specimen at high angles of incidence.

Light returned from the surface of the specimen may be reflected byobjective lens 120 and one of the mirrors to analyzer 122. Analyzer 122may be configured to split the light returned from the surface of thespecimen into two reflected light beams based on the polarization stateof the light. For example, analyzer 112 may be configured to generatetwo separate beams of light having substantially different polarizationstates. As shown in FIG. 11 b, measurement device may also includeautofocus sensor 124. Autofocus sensor 124 may include a splitphotodiode detector configured to receive a substantially focused imageof the illuminated spot on the specimen. The focused image of the spotmay be provided by beam splitter 125 positioned along an optical pathbetween analyzer 122 and mirror 118. For example, the beam splitter maybe configured to direct a portion of the light returned from specimen104 to the autofocus sensor. Autofocus sensor 124 may include twophotodiodes configured to measure an intensity of the image and to senda signal representative of the measured intensity to a processor. Theoutput of autofocus sensor may be called a focus signal. The focussignal may be a function of sample position. The processor may beconfigured to determine a focus position of the specimen with respect tothe measurement device using a position of an extremum in the focussignal.

The measurement device may also include mirror 126 configured to directlight returned from the surface of the specimen to spectrometer 128.Spectrometer 128 may be configured to measure an intensity of the s andp components of reflectance across a spectrum of wavelengths. The term“s component” is generally used to describe the component of polarizedradiation having an electrical field that is substantially perpendicularto the plane of incidence of the reflected beam. The term “p component”is generally used to describe the component of polarized radiationhaving an electrical field in the plane of incidence of the reflectedbeam. The measured reflectance spectrum may be used to determine acritical dimension, a height, and a sidewall angle of a feature on thesurface of the specimen as described herein. For example, a relativereflectance spectrum may be obtained by dividing the intensity of thereturned light at each wavelength measured by spectrometer 128 by arelative reference intensity at each wavelength measured by referencespectrometer 110 of the measurement device. The relative reflectancespectrum may be fitted to a theoretical model of the data such that acritical dimension, a height, and a sidewall angle may be determined.

In an embodiment, as shown in FIG. 9, measurement device 74 andmeasurement device 76 of system 70 may be configured as a coherenceprobe microscope, an interference microscope, or an opticalprofilometer. For example, a coherence probe microscope may beconfigured as a specially adapted Linnik microscope in combination witha video camera, a specimen transport stage, and data processingelectronics. Alternatively, other interferometric optical profilingmicroscopes and techniques such as Fringes of Equal Chromatic Order(“FECO”), Nomarski polarization interferometer, differentialinterference contrast (“DIC”), Tolansky multiple-beam interferometry,and two-beam-based interferometry based on Michelson, Fizeau, and Miraumay be adapted to the system. The measurement device may utilize eitherbroad band or relatively narrow band light to develop a plurality ofinterference images taken at different axial positions (elevations)relative to the surface of a specimen. The interference images mayconstitute a series of image planes. The data in these planes may betransformed by an additive transformation on video signal intensities.The transformed image data may be used to determine an absolute mutualcoherence between the object wave and reference wave for each pixel inthe transformed plane. Synthetic images may be formed whose brightnessmay be proportional to the absolute mutual coherence as the optical pathlength is varied.

In an embodiment, a measurement device configured as an interferencemicroscope may include an energy source such as a xenon lamp configuredto emit an incident beam of light. An appropriate energy source may alsoinclude a light source configured to emit coherent light such as lightthat may be produced by a laser. The measurement device may furtherinclude additional optical components configured to direct the incidentbeam of light to a surface of the specimen. Appropriate additionaloptical components may include condenser lenses, filters, diffusers,aperture stops, and field stops. Additional optical components may alsoinclude beam splitters, microscopic objectives, and partiallytransmissive mirrors.

The optical components may be arranged within the measurement devicesuch that a first portion of the incident beam of light may be directedto a surface of a specimen. The optical components may be furtherarranged within the measurement device such that a second portion of theincident beam of light may be directed to a reference mirror. Forexample, the second portion of the incident beam of light may begenerated by passing the incident beam of light through a partiallytransmissive mirror prior to directing the sample beam to a surface ofthe specimen. Light reflected from the surface of the specimen may thenbe combined with light reflected from the reference mirror. In anembodiment, the detection system may include a conventionalinterferometer. The reflected incident beam of light may be combinedwith the reference beam prior to striking the interferometer. Since theincident beam of light reflected from the surface of the specimen andthe reference beam reflected from the reference mirror are not in phase,interference patterns may develop in the combined beam. Intensityvariations of the interference patterns in the combined beam may bedetected by the interferometer.

The interferometer may be configured to generate a signal responsive tothe detected intensity variations of the interference patterns of thecombined beam. The generated signal may be processed to provide surfaceinformation about the measured surface. The measurement device may alsoinclude a spotter microscope to aid in control of the incident beam oflight. The spotter microscope may be electronically coupled to themeasurement device to provide some control of the incident beam oflight. Examples of interference microscopes and methods of use areillustrated in U.S. Pat. No. 5,112,129 to Davidson et al., U.S. Pat. No.5,438,313 to Mazor et al., U.S. Pat. No. 5,712,707 to Ausschnitt et al.,U.S. Pat. No. 5,757,507 to Ausschnitt et al., U.S. Pat. No. 5,805,290 toAusschnitt et al., U.S. Pat. No. 5,914,784 to Ausschnitt et al., andU.S. Pat. No. 6,023,338 to Bareket, all of which are incorporated byreference as if fully set forth herein.

In an additional embodiment, a measurement device configured as anoptical profilometer may be used to determine a height of a surface of aspecimen. Optical profilometers may be configured to use lightscattering techniques, light sectioning, and various interferometricoptical profiling techniques as described herein. An opticalprofilometer may be configured to measure interference between light ontwo beam paths. As a height of a surface of a specimen changes, one ofthe beam path lengths may change thereby causing a change in theinterference patterns. Therefore, the measured interference patterns maybe used to determine a height of a surface of a specimen. A Nomarskipolarization interferometer may be suitable for use as an opticalprofilometer.

In an embodiment, an optical profilometer may include a light sourcesuch as a tungsten halogen bulb configured to emit an incident beam. Thelight source may be configured to emit light of various wavelengths suchas infrared light, ultraviolet light, and/or visible light. The lightsource may also be configured to emit coherent light such as lightproduced from a laser. The optical profilometer may also include opticalcomponents configured to direct the light to a surface of a specimen.Such optical components may include any of the optical components asdescribed herein. The optical profilometer may further include arotating analyzer configured to phase shift the electromagneticradiation, a charge coupled device (“CCD”) camera, a frame grabber, andelectronic processing circuits. A frame grabber is a device that may beconfigured to receive a signal from a detector such as a CCD camera andto convert the signal (i.e., to digitize an image). A quarter wavelengthplate and spectral filter may also be included in the opticalprofilometer. A polarizer and Nomarski prism may be configured toilluminate the specimen with two substantially orthogonally polarizedbeams laterally offset on the specimen surface by a distance smallerthan the resolution limit of the objectives. After returned from thespecimen, the light beams may be recombined by the Nomarski prism.

In an embodiment, the optical profilometer may include a conventionalinterferometer. Interference patterns of the recombined light beams maybe detected by the interferometer. The detected interference patternsmay be used to determine a surface profile of the specimen. An exampleof an optical profilometer is illustrated in U.S. Pat. No. 5,955,661 toSamsavar et al., which is incorporated by reference as if fully setforth herein. An example of a measurement device configured to determineoverlay misregistration is illustrated in U.S. patent application Ser.No. 09/639,495, “Metrology System Using Optical Phase,” to Nikoonahad etal., filed Aug. 14, 2000, issued as U.S. Pat. No. 6,710,876 on Mar. 23,2004, and is incorporated by reference as if fully set forth herein.

In an embodiment, measurement device 78 may be configured as a patternrecognition device. Measurement device 78 may include a light sourcesuch as a lamp configured to emit broadband light, which may includevisible and ultraviolet radiation. The measurement device may alsoinclude a beam splitting mirror configured to direct a portion of thelight emitted by the light source to an objective thereby forming asample beam of light. The objective may include reflective objectiveshaving several magnifications. For example, the objective may include a15× Schwartzchild design all-reflective objective, a 4× Nikon CFN PlanApochromat, and a 1× UV transmissive objective. The three objectives maybe mounted on a turret configured to rotate such that one of the threeobjectives may be placed in a path of the sample beam of light. Theobjective may be configured to direct the sample beam of light to asurface of a specimen.

Light returned from the surface of the specimen may pass back throughthe objective and the beam splitting mirror to a sample plate of themeasurement device. The sample plate may be a reflective fused silicaplate with an aperture formed through the plate. The light returned fromthe surface of the specimen may be partially reflected off of the sampleplate and through a relatively short focal length achromat. The returnedlight may be reflected from a folding mirror to a beam splitter cube.The beam splitter cube may be configured to direct a portion of thereturned light to a pentaprism. The pentaprism may be configured toreflect the portion of the returned light. The reflected portion of thereturned light may also pass through additional optical components ofmeasurement device 78 such as a relatively long focal length achromatand a filter. The reflected portion of the returned light may pass to afolding mirror configured to direct the returned light to a videocamera. In addition, the video camera may be configured to generate anon-inverted image of the surface of the specimen. An example of apattern recognition device is illustrated in U.S. Pat. No. 5,910,842 toPiwonka-Corle et al., and is incorporated by reference as if fully setforth herein.

In an additional embodiment, the measurement device may be configured asa non-imaging scatterometer, a scatterometer, or a spectroscopicscatterometer. Scatterometry is a technique involving the angle-resolvedmeasurement and characterization of light scattered from a structure.For example, structures arranged in a periodic pattern on a specimensuch as repeatable pattern features may scatter or diffract incidentlight into different orders. A diffracted light pattern from a structuremay be used as a “fingerprint” or “signature” for identifying a propertyof the repeatable pattern features. For example, a diffracted lightpattern may be analyzed to determine a property of repeatable patternfeatures on a surface of a specimen such as a period, a width, a stepheight, a sidewall angle, a thickness of underlying layers, and aprofile of feature on a specimen.

A scatterometer may include a light source configured to direct light ofa single wavelength toward a surface of the specimen. For example, thelight source may include a gas laser or a solid state laser diode.Alternatively, the light source may be configured to direct light ofmultiple wavelengths toward a surface of the specimen. As such, thescatterometer may be configured as a spectroscopic scatterometer. In anexample, the light source may be configured to emit broadband radiation.An appropriate broadband light source may include a white light sourcecoupled to a fiber optic cable configured to randomize a polarizationstate of the emitted light and may create a substantially uniformincident beam of light. Light emitted from the fiber optic cable maypass through a plurality of optical components arranged within themeasurement device. For example, light emitted from the fiber opticcable may pass through a slit aperture configured to limit a spot sizeof the incident beam of light. A spot size may be generally defined as asurface area of a specimen that may be illuminated by an incident beamof light. Light emitted from the fiber optic cable may also pass througha focusing lens. Furthermore, light emitted from the fiber optic cablemay be further passed through a polarizer configured to produce anincident beam of light having a known polarization state. The incidentbeam of light having a known polarization state may be directed to asurface of the specimen.

The scatterometer may also include a detection system that may include aspectrometer. The spectrometer may be configured to measure an intensityof different wavelengths of light scattered from a surface of aspecimen. In an embodiment, the zeroth diffraction order intensity maybe measured. Although for some repeatable pattern features, measurementof higher diffraction order intensities may also be possible. A signalresponsive to the zeroth and/or higher diffraction order intensities atdifferent wavelengths generated by the spectrometer may be sent to aprocessor coupled to the spectrometer. The processor may be configuredto determine a signature of a structure on a surface of the specimen. Inaddition, the processor may be configured to determine a property ofrepeatable pattern features on the surface of the specimen. For example,the processor may be further configured to compare the determinedsignature to signatures of a database. Signatures of the database mayinclude signatures determined experimentally with specimens having knowncharacteristics and/or signatures determined by modeling. A property ofa repeatable pattern feature may include a period, a width, a stepheight, a sidewall angle, a thickness of underlying layers, and aprofile of the features on a specimen.

As described above, the scatterometer may include a polarizer coupled tothe illumination system. The polarizer may be further configured totransmit light emitted by a light source of the illumination system of afirst polarization state and to reflect light emitted by a light sourceof a second polarization state. In addition, the scatterometer may alsoinclude an analyzer coupled to the detection system. The analyzer may beconfigured to transmit light of substantially the same polarizationstate as the polarizer. For example, the analyzer may be configured totransmit light scattered from the surface of the specimen having thefirst polarization state. In an additional embodiment, the spectrometermay include a stage coupled to the illumination system and the detectionsystem. The stage may be configured as described herein. In this manner,characteristics of repeatable pattern features having substantiallydifferent characteristics formed on a surface of a specimen may bedetermined sequentially or simultaneously. Examples of measurementdevices are illustrated in PCT Application No. WO 99/45340 to Xu et al.,and is incorporated by reference as if fully set forth herein.Additional examples of measurement devices configured to measure lightscattered from a specimen are illustrated in U.S. Pat. No. 6,081,325 toLeslie et al., U.S. Pat. No. 6,201,601 to Vaez-Iravani et al., and U.S.Pat. No. 6,215,551 to Nikoonahad et al., and are incorporated byreference as if fully set forth herein.

A measurement device such as a scatterometer may be either an imagingdevice or a non-imaging device. In imaging devices, a lens may capturelight scattered from a surface of a specimen. The lens may also preservespatial information encoded in the reflected light (e.g., a spatialdistribution of light intensity). In addition, the scatterometer mayinclude a detector configured as an array of light sensitive devicessuch as a charge-coupled device (“CCD”) camera, a CMOS photodiode, or aphotogate camera. Alternatively, in non-imaging devices, light from alight source may be directed to a relatively small area on a surface ofa specimen. A detector such as a photomultiplier tube, a photodiode, oran avalanche photodiode may detect scattered or diffracted light and mayproduce a signal proportional to the integrated light intensity of thedetected light.

In an additional embodiment, the measurement device may be configured asa bright field imaging device, a dark field imaging device, or a brightfield and dark field imaging device. “Bright field” generally refers toa collection geometry configured to collect specularly reflected lightfrom a specimen. A bright field collection geometry may have any angleof incidence although typically it may have an angle of incidence normalto the specimen plane. A bright field imaging device may include a lightsource configured to direct light to a surface of a specimen. The lightsource may also be configured to provide substantially continuousillumination of a surface of a specimen. The light source may be, forexample, a fluorescent lamp tube. Continuous illumination may also beachieved by a string of point light sources coupled to a light diffusingelement. The light source may also include any of the light sources asdescribed herein.

A bright field imaging device may also include a bright field imagingsystem configured to collect bright field light propagating along abright field path from the surface of a specimen. The bright field lightmay include light specularly reflected from the surface of the specimen.The bright field imaging system may include optical components such asslit mirrors and an imaging lens. The slit mirrors may be configured todirect bright field light propagating along a bright field path from thesurface of a specimen to the imaging lens. The imaging lens may beconfigured to receive bright field light reflected from the slitmirrors. The imaging lens may be, for example, a fixed lens configuredto reduce optical aberrations in the bright field light and to reduceeffects of intensity reduction at an edge of the imaging field. Theimaging lens may also be configured to concentrate light passing throughthe lens onto light sensitive devices positioned behind the imaginglens. The light sensitive devices may include, but are not limited to,an 8000 PN diode element line scan sensor array, a CCD camera, a TDIcamera, or other suitable device type.

One or more output signals of the light sensitive devices may betransmitted to an image computer for processing. An image computer maybe a parallel processing system that may be commonly used by the machinevision industry. The image computer may also be coupled to a hostcomputer configured to control the bright field imaging device and toperform data processing functions. For example, data processingfunctions may include determining a presence of defects on a surface ofa specimen by comparing multiple output signals of the light sensitivedevices generated by illuminating multiple locations on the specimen.Multiple locations on the specimen may include, for example, two dies ofa specimen, as illustrated in FIG. 1.

“Dark field” generally refers to a collection geometry configured tocollect only scattered light from a specimen. “Double dark field”generally refers to an inspection geometry using a steep angle obliqueillumination, and a collection angle outside of the plane of incidence.Such an arrangement may include a near-grazing illumination angle and anear-grazing collection angle to suppress surface scattering. Thissuppression occurs because of the dark fringe (also known as the Weinerfringe) near the surface that may occur due to interfering incident andreflected waves. A dark field imaging device may include any of thelight sources as described herein. A double dark field device may beeither an imaging device or a non-imaging device.

A dark field imaging device may also include a dark field imaging systemconfigured to collect dark field light propagating along a dark fieldpath from the surface of a specimen. The dark field imaging system mayinclude optical components, an image computer, and a host computer asdescribed herein. In this manner, a presence of defects on a surface ofa specimen may be determined from a dark field image of the specimen asdescribed herein. An example of an inspection system configured for darkfield imaging is illustrated in PCT Application No. WO 99/31490 toAlmogy, and is incorporated by reference as if fully set forth herein.

In addition, a measurement device may include bright field and darkfield light sources, which may include one or more light sources. Eachof the light sources may be arranged at different angles of incidencewith respect to the surface of the specimen. Alternatively, each of thelight sources may be arranged at the same angle of incidence withrespect to the surface of the specimen. The measurement device may alsoinclude bright field and dark field imaging systems as described above.For example, the measurement device may include one or more imagingsystems. Each of the imaging systems may be arranged at different anglesof incidence with respect to the surface of the specimen. Alternatively,each of the imaging systems may be arranged at the same angle ofincidence with respect to the surface of the specimen. As such, themeasurement device may be configured to operate as a bright field anddark field imaging device. Each of the imaging systems may be coupled tothe same image computer, which may be configured as described above. Inaddition, the image computer may be coupled to a host computer, whichmay be configured as described above. The host computer may also beconfigured to control both the bright field components and the darkfield components of the measurement device.

The bright field, dark field, and bright field and dark field devices,however, may also be configured as non-imaging devices. For example, thedetectors described above may be replaced with a photomultiplier tube, aphotodiode, or an avalanche photodiode. Such detectors may be configuredto produce a signal proportional to the integrated light intensity ofthe bright field light and/or the dark field light.

FIG. 12 illustrates a schematic side view of an alternate embodiment ofsystem 32 configured to determine at least two properties of a specimenduring use. As will be further described herein, elements of system 32which may be similarly configured in each of the embodiments illustratedin FIGS. 3-7 and 12 have been indicated by the same referencecharacters. For example, stage 42 may be similarly configured in each ofthe embodiments illustrated in FIGS. 3-7 and 12.

As used herein, the terms “front side” and “back side” generally referto opposite sides of a specimen. For example, the term, a “front side”,or “upper surface,” of a specimen such as a wafer may be used to referto a surface of the wafer upon which semiconductor devices may beformed. Likewise, the term, a “back side”, or a “bottom surface,” of aspecimen such as a wafer may be used to refer to a surface of the waferwhich is substantially free of semiconductor devices.

System 32 may include stage 42 configured to support specimen 40. Asshown in FIG. 12, stage 42 may contact a back side of the specimenproximate to an outer lateral edge of the specimen to support thespecimen. For example, the stage may include a robotic wafer handlerconfigured to support a specimen. In alternative embodiments, an uppersurface of the stage may be configured to have a surface area less thana surface area of the back side of the specimen. In this manner, stage42 may contact a back side of the specimen proximate to a center, or aninner surface area, of the specimen to support the specimen. In anexample, the stage may include a vacuum chuck or an electrostatic chuck.Such a stage may be disposed within a process chamber of a process toolsuch as a semiconductor fabrication process tool and may be configuredto support the specimen during a process step such as a semiconductorfabrication process step. Such a stage may also be included in any ofthe other measurement devices as described herein.

System 32 may include a measurement device coupled to the stage. Themeasurement device may include a plurality of energy sources 44. A firstof the plurality of energy sources 44 may be configured to direct energytoward front side 40 a of specimen 40. As shown in FIG. 12, twodetectors 46 a and 46 b may be coupled to the first of the plurality ofenergy sources. The two detectors may be positioned at different angleswith respect to the first energy source. In this manner, each of thedetectors may be configured to detect different types of energypropagating from front side 40 a of specimen 40. For example, detectors46 b may be configured to detect dark field light propagating from thefront side of specimen 40. In addition, detector 46 a may be configuredto detect bright field light propagating from the front side of specimen40. In an alternative embodiment, however, a single detector, eitherdetector 46 a or detector 46 b, may be included in the measurementdevice and may be coupled to the first energy source. Additionalcomponents such as component 48 may also be coupled to the first energysource. For example, component 48 may include any of the opticalcomponents as described herein.

The measurement device may also include component 50. Component 50 mayinclude, for example, a beam splitter configured to transmit light fromthe light source toward specimen 40 and to reflect light propagatingfrom specimen 40 toward detector 46 a. The measurement device may alsoinclude additional component 52 coupled to detector 46 a. Component 52may be configured as described in above embodiments. In addition, such acomponent may also be coupled to detector 46 b. The position and theconfiguration of each of the components may vary, however, depending on,for example, the properties of the specimen to be measured with thesystem.

In an embodiment, a second of the plurality of energy sources 44 may beconfigured to direct energy toward back side 40 b of specimen 40. Themeasurement device may also include detector 46 c coupled to the secondenergy source. In addition, multiple detectors may be coupled to thesecond energy source. Detector 46 c may be positioned with respect tothe second energy source such that a particular type of energypropagating from back side 40 b of specimen 40 may be detected. Forexample, detector 46 c may be positioned with respect to the secondenergy source such that dark field light propagating along a dark fieldpath from the back side 40 b of specimen 40 may be detected. Additionalcomponent 48 may also be coupled to the second energy source. Component48 may include any of the optical components as described herein.Furthermore, system 32 may include processor 54. Processor 54 may becoupled to each of the detectors 46 a, 46 b, and 46 c, as shown in FIG.12. The processor may be configured as described herein.

According to the above embodiment, therefore, system 32 may beconfigured to determine at least two properties on at least two surfacesof a specimen. For example, system 32 may be configured to determine apresence of defects on a front side of the specimen. In addition, system32 may be configured to determine a presence of defects on a back sideof the specimen. Furthermore, the system may be configured to determinea presence of defects on an additional surface of the specimen. Forexample, the system may be configured to determine a presence of defectson a front side, a back side, and an edge of the specimen. As usedherein, the term “an edge” of a specimen generally refers to an outerlateral surface of the specimen substantially normal to the front andback sides of the specimen. Furthermore, the system may also beconfigured to determine a presence of defects on more than one surfaceof the specimen simultaneously.

In an additional embodiment, the system may also be configured todetermine a number of defects on one or more surfaces of a specimen, alocation of defects on one or more surfaces of a specimen, and/or a typeof defects on one or more surfaces of a specimen sequentially orsubstantially simultaneously. For example, the processor may beconfigured to determine a number, location, and/or type of defects onone or more surfaces of a specimen from the energy detected by themeasurement device. Examples of methods for determining the type ofdefect present on a surface of a specimen are illustrated in U.S. Pat.No. 5,831,865 to Berezin et al., and is incorporated by reference as iffully set forth herein. Additional examples of methods for determiningthe type of defects present on a surface of a specimen are illustratedin WO 99/67626 to Ravid et al., WO 00/03234 to Ben-Porath et al., and WO00/26646 to Hansen, and are incorporated by reference as if fully setforth herein.

Furthermore, processor 54 may be further configured to determine atleast three properties of the specimen. The three properties may includea critical dimension of the specimen, an overlay misregistration of thespecimen, and a presence, a number, a location, and/or a type of defectson one or more surfaces of the specimen. In this manner, the system maybe configured to determine a critical dimension of the specimen, anoverlay misregistration of the specimen, and a presence, a number, alocation, and/or a type of defects on one or more surfaces of thespecimen sequentially or substantially simultaneously.

The system may be configured to determine micro and/or macro defects onone or more surfaces of a specimen sequentially or substantiallysimultaneously. An example of a system configured to determine macro andmicro defects sequentially is illustrated in U.S. Pat. No. 4,644,172 toSandland et al., which is incorporated by reference as if fully setforth herein. Macro-micro optics, as described by Sandland, may beincorporated into a measurement device, as described herein, which maybe coupled to one stage. The stage may be configured as describedherein. In this manner, the macro-micro optics of Sandland may beconfigured to determine micro and/or macro defects on one or moresurfaces of a specimen substantially simultaneously. In addition, themacro-micro optics of Sandland may be configured to determine micro andmacro defects on one or more surfaces of a specimen sequentially whilethe specimen is disposed on a single stage. Alternatively, themeasurement device may include optical components configured asillustrated in U.S. Pat. No. 5,917,588 to Addiego, which is incorporatedby reference as if fully set forth herein. For example, a measurementdevice, as described herein, may include micro optics, as described bySandland, coupled to macro optics of the after develop inspection(“ADI”) Macro inspection system, as described by Addiego.

Micro defects may typically have a lateral dimension of less thanapproximately 25 μm. Macro defects may include yield-limiting largescale defects having a lateral dimension of greater than about 25 μm.Such large scale defects may include resist or developer problems suchas lifting resist, thin resist, extra photoresist coverage, incompleteor missing resist, which may be caused by clogged dispense nozzles or anincorrect process sequence, and developer or water spots. Additionalexamples of macro defects may include regions of defocus (“hot spots”),reticle errors such as tilted reticles or incorrectly selected reticles,scratches, pattern integrity problems such as over or under developingof the resist, contamination such as particles or fibers, andnon-uniform or incomplete edge bead removal (“EBR”). The term “hotspots” generally refers to a photoresist exposure defect that may becaused, for example, by a depth of focus limitation of an exposure tool,an exposure tool malfunction, a non-planar surface of a specimen at thetime of exposure, foreign material on a back side of a specimen or on asurface of a supporting device, or a design constraint. For example,foreign material on the back side of the specimen or on the surface of asupporting device may effectively deform the specimen. Such deformationof the specimen may cause a non-uniform focal surface during an exposureprocess. In addition, such a non-uniform focal surface may be manifestedon the specimen as an unwanted or missing pattern feature change.

Each of the above described defects may have a characteristic signatureunder either dark field or bright field illumination. For example,scratches may appear as a bright line on a dark background under darkfield illumination. Extra photoresist and incomplete photoresistcoverage, however, may produce thin film interference effects underbright field illumination. In addition, large defocus defects may appearas a dim or bright pattern in comparison to a pattern produced by alaterally proximate die under dark field illumination. Other defectssuch as defects caused by underexposure or overexposure of the resist,large line width variations, large particles, comets, striations,missing photoresist, underdeveloped or overdeveloped resist, anddeveloper spots may have characteristic signatures under bright fieldand dark field illumination.

As shown in FIG. 1, a surface of specimen 10 may have a plurality ofdefects. Defect 14 on the surface of specimen 10 may be incompleteresist coverage. For example, incomplete resist coverage may be causedby a malfunctioning coating tool or a malfunctioning resist dispensesystem. Defect 16 on the surface of specimen 10 may be a surfacescratch. Defect 18 on the surface of specimen 10 may be a non-uniformregion of a layer of resist. For example, such a non-uniform region ofthe resist may be caused by a malfunctioning coating tool or amalfunctioning post apply bake tool. Defect 20 on the surface ofspecimen 10 may be a hot spot. In addition, defect 22 on the surface ofspecimen 10 may be non-uniform edge bead removal (“EBR”). Each of thedefects described above may be present in any location on a surface ofspecimen 10. In addition, any number of each of the defects may also bepresent on the surface of the specimen.

Additional examples of methods and systems for determining a presence ofdefects on a surface of a specimen are illustrated in U.S. Pat. No.4,247,203 to Levy et al., U.S. Pat. No. 4,347,001 to Levy et al., U.S.Pat. No. 4,378,159 to Galbraith, U.S. Pat. No. 4,448,532 to Joseph etal., U.S. Pat. No. 4,532,650 to Wihl et al., U.S. Pat. No. 4,555,798 toBroadbent, Jr. et al., U.S. Pat. No. 4,556,317 to Sandland et al., U.S.Pat. No. 4,579,455 to Levy et al., U.S. Pat. No. 4,601,576 to Galbraith,U.S. Pat. No. 4,618,938 to Sandland et al., U.S. Pat. No. 4,633,504 toWihl, U.S. Pat. No. 4,641,967 to Pecen, U.S. Pat. No. 4,644,172 toSandland et al., U.S. Pat. No. 4,766,324 to Saadat et al., U.S. Pat. No.4,805,123 to Specht et al., U.S. Pat. No. 4,818,110 to Davidson, U.S.Pat. No. 4,845,558 to Tsai et al., U.S. Pat. No. 4,877,326 to Chadwicket al., U.S. Pat. No. 4,898,471 to Vaught et al., U.S. Pat. No.4,926,489 to Danielson et al., U.S. Pat. No. 5,076,692 to Neukermans etal., U.S. Pat. No. 5,189,481 to Jann et al., U.S. Pat. No. 5,264,912 toVaught et al., U.S. Pat. No. 5,355,212 to Wells et al., U.S. Pat. No.5,537,669 to Evans et al., U.S. Pat. No. 5,563,702 to Emery et al., U.S.Pat. No. 5,565,979 to Gross, U.S. Pat. No. 5,572,598 to Wihl et al.,U.S. Pat. No. 5,604,585 to Johnson et al., U.S. Pat. No. 5,737,072 toEmery et al., U.S. Pat. No. 5,798,829 to Vaez-Iravani, U.S. Pat. No.5,633,747 to Nikoonahad, U.S. Pat. No. 5,822,055 to Tsai et al., U.S.Pat. No. 5,825,482 to Nikoonahad et al., U.S. Pat. No. 5,864,394 toJordan, III et al., U.S. Pat. No. 5,883,710 to Nikoonahad et al., U.S.Pat. No. 5,917,588 to Addiego, U.S. Pat. No. 6,020,214 to Rosengaus etal., U.S. Pat. No. 6,052,478 to Wihl et al., U.S. Pat. No. 6,064,517 toChuang et al., U.S. Pat. No. 6,078,386 to Tsai et al., U.S. Pat. No.6,081,325 to Leslie et al., U.S. Pat. No. 6,175,645 to Elyasaf et al.,U.S. Pat. No. 6,178,257 to Alumot et al., U.S. Pat. No. 6,122,046 toAlmogy, and U.S. Pat. No. 6,215,551 to Nikoonahad et al., all of whichare incorporated by reference as if fully set forth herein. Additionalexamples of defect inspection methods and apparatuses are illustrated inPCT Application Nos. WO 99/38002 to Elyasaf et al., WO 00/68673 toReinhron et al., WO 00/70332 to Lehan, WO 01/03145 to Feuerbaum et al.,and WO 01/13098 to Almogy et al., and are incorporated by reference asif fully set forth herein. Further examples of defect inspection methodsand apparatuses are illustrated in European Patent Application Nos. EP 0993 019 A2 to Dotan, EP 1 061 358 A2 to Dotan, EP 1 061 571 A2 toBen-Porath, EP 1 069 609 A2 to Harvey et al., EP 1 081 489 A2 to Karpolet al., EP 1 081 742 A2 to Pearl et al., and EP 1 093 017 A2 to Kenan etal., which are incorporated by reference as if fully set forth herein.As such, the embodiments described above may also include features ofany of the systems and methods illustrated in all of the patents whichhave been incorporated by reference herein.

In a further embodiment, the systems as described herein may also beconfigured to determine a flatness measurement of the specimen.“Flatness” may be generally defined as an average of the topographiccharacteristics of an upper surface of the specimen across a surfacearea of the specimen. For example, the topographic characteristics mayinclude, but are not limited to, a roughness of an upper surface of aspecimen and a planar uniformity of an upper surface of a layer arrangedon the specimen. Roughness and planar uniformity of the upper surface ofa layer may vary depending on, for example, processes performed on thespecimen prior to measurement, which may include, in an example ofsemiconductor fabrication, etch, deposition, plating,chemical-mechanical polishing, or coating.

As described herein, a processor may be configured to determine at leastthree properties of the specimen from the detected energy. The threeproperties may include a critical dimension of the specimen, an overlaymisregistration of the specimen, and a flatness of the specimen. Inaddition, the process may be configured to determine four properties ofthe specimen from the detected energy. The four properties may includecritical dimension, overlay misregistration, flatness, and a presence, anumber, a location, and/or a type of defects on the specimen. As such,the system may be configured to determine a critical dimension of thespecimen, an overlay misregistration of the specimen, a flatnessmeasurement, and/or a presence, a number, a location, and/or a type ofdefects on a surface of the specimen sequentially or substantiallysimultaneously.

FIG. 13 illustrates a schematic top view of an embodiment of system 32coupled to a semiconductor fabrication process tool. For example, thesystem may be coupled to lithography tool 130. A lithography tool, whichmay be commonly referred to a lithography track or cluster tool, mayinclude a plurality of process chambers 132, 144, 146, 148, 150, 154,and 156. The number and configuration of the process chambers may varydepending on, for example, the type of wafers processed in thelithography tool. Examples of lithography tools and processes areillustrated in U.S. Pat. No. 5,393,624 to Ushijima, U.S. Pat. No.5,401,316 to Shiraishi et al., U.S. Pat. No. 5,516,608 to Hobbs et al.,U.S. Pat. No. 5,968,691 to Yoshioka et al., and U.S. Pat. No. 5,985,497to Phan et al., and are incorporated by reference as if fully set forthherein. Lithography tool 130 may be coupled to an exposure tool, whichmay include exposure chamber 134. A first portion of the processchambers may be configured to perform a step of a lithography processprior to exposure of a resist. A second portion of the process chambersmay be configured to perform a step of the lithography processsubsequent to exposure of the resist.

In an embodiment, lithography tool 130 may also include at least onerobotic wafer handler 136. Robotic wafer handler 136 may be configuredto move a specimen from a first process chamber to a second processchamber. For example, the robotic wafer handler may be configured tomove along a direction generally indicated by vector 138. In addition,the robotic wafer handler may also be configured to rotate in adirection indicated by vector 140 such that a specimen may be moved froma first process chamber located on first side of the lithography tool toa second process chamber located on a second side of the lithographytool. The first side and the second side may be located on substantiallyopposite sides of the lithography tool. The robotic wafer handler mayalso be configured to move a specimen from lithography tool 130 toexposure chamber 134 of the exposure tool. In this manner, the roboticwafer handler may move a specimen sequentially through a series ofprocess chambers such that a lithography process may be performed on thespecimen.

The robotic wafer handler may be also configured to move specimen 139from cassette 141 disposed within load chamber 142 of the lithographytool to a process chamber of the lithography tool. The cassette may beconfigured to hold a number of specimens which may be processed duringthe lithography process. For example, the cassette may be a frontopening unified pod (“FOUP”). The robotic wafer handler may beconfigured to dispose the specimen in a process chamber such as surfacepreparation chamber 144. The surface preparation chamber may beconfigured to form an adhesion promoting chemical such ashexamethyldisilazane (“HMDS”) on the surface of the specimen. HMDS maybe deposited at a temperature of approximately 80° C. to approximately180° C. Subsequent to the surface preparation process, the robotic waferhandler may be configured to remove the specimen from surfacepreparation chamber 144 and place the specimen into chill chamber 146.As such, chill chamber 146 may be configured to reduce a temperature ofthe specimen to a temperature suitable for subsequent processing (e.g.,approximately 20° C. to approximately 25° C.).

In an additional embodiment, an anti-reflective coating may be formed onthe surface of the specimen. The anti-reflective coating may be formedon the specimen by spin coating followed by a post apply bake process.Since the post apply bake process for an anti-reflective coatinggenerally may involve heating a coated specimen from approximately 170°C. to approximately 230° C., a chill process may also be performedsubsequent to this post apply bake process.

A resist may be also formed upon the specimen. The robotic wafer handlermay be configured to place the specimen into resist apply processchamber 148. A resist may be automatically dispensed onto an uppersurface of the specimen. The resist may be distributed across thespecimen by spinning the specimen at a high rate of speed. The spinningprocess may dry the resist such that the specimen may be removed fromthe resist apply process chamber without adversely affecting the coatedresist. The robotic wafer handler may be configured to move the specimenfrom resist apply process chamber 148 to post apply bake process chamber150. The post apply bake process chamber may be configured to heat theresist-coated specimen at a temperature of approximately 90° C. toapproximately 140° C. The post apply bake process may be used to drivesolvent out of the resist and to alter a property of the resist such assurface tension. Subsequent to the post apply bake process, the roboticwafer handler may be configured to move the specimen from the post applybake process chamber 150 to chill process chamber 146. In this manner, atemperature of the specimen may be reduced to approximately 20° C. toapproximately 25° C.

The robotic wafer handler may also be configured to move the specimenfrom chill process chamber 146 to exposure chamber 134. The exposurechamber may include interface system 152 coupled to lithography tool130. Interface system 152 may include mechanical device 153 configuredto move specimens between the lithography tool and the exposure chamber.The exposure tool may be configured to align a specimen in the exposurechamber and to expose the resist to energy such as deep-ultravioletlight. In addition, the exposure tool may be configured to expose theresist to a particular intensity of energy, or dose, and a particularfocus condition. Many exposure tools may be configured to alter dose andfocus conditions across a specimen, for example, from die to die. Theexposure system may also be configured to expose an outer lateral edgeof the specimen. In this manner, resist disposed proximal an outerlateral edge of the specimen may be removed. Removing the resist at theouter lateral edge of a specimen may reduce contamination in subsequentprocesses.

The robotic wafer handler may be further configured to move the specimenfrom exposure chamber 134 to post exposure bake process chamber 154. Thespecimen may then be subjected to a post exposure bake process step. Forexample, the post exposure bake process chamber may be configured toheat the specimen to a temperature of approximately 90° C. toapproximately 150° C. A post exposure bake process may drive a chemicalreaction in a resist, which may enable portions of the resist to beremoved in subsequent processing. As such, the performance of the postexposure process may be critical to the overall performance of thelithography process.

Subsequent to the post exposure process, the robotic wafer handler maybe configured to move the specimen from post expose bake process chamber154 to chill process chamber 146. After the specimen has been chilled,the robotic wafer handler may be configured to move the specimen todevelop process chamber 156. The develop process chamber may beconfigured to sequentially dispense a developer chemical and water onthe specimen such that a portion of the resist may be removed. As such,resist remaining on the specimen may be patterned. Subsequent to thedevelop process step, the robotic wafer handler may be configured tomove the specimen from the develop process chamber to a hard bakeprocess chamber or a post develop bake process chamber. A hard bakeprocess may be configured to heat a specimen to a temperature ofapproximately 90° C. to approximately 130° C. A hard bake process maydrive contaminants and any excess water from the resist and thespecimen. The temperature of the specimen may be reduced by chillprocess as described herein.

In an embodiment, system 32 may be arranged laterally proximate tolithography tool 130 or another semiconductor fabrication process tool.As shown in FIG. 13, system 32 may be located proximate cassette end 160of lithography tool 130 or proximate exposure tool end 162 oflithography tool 130. In addition, a location of system 32 with respectto lithography tool 130 may vary depending on, for example, aconfiguration of the process chambers within lithography tool 130 andclean room constraints for space surrounding lithography tool 130. In analternative embodiment, system 32 may be disposed within lithographytool 130. A position of system 32 within lithography tool 130 may varydepending on, for example, a configuration of the process chamberswithin lithography tool 130. In addition, a plurality of systems 32 maybe arranged laterally proximate and/or disposed within lithography tool130. Each system may be configured to measure at least two differentproperties of a specimen. Alternatively, each system may be similarlyconfigured.

In either of these embodiments, robotic wafer handler 136 may beconfigured to move a specimen from lithography tool 130 to a stagewithin system 32. For example, robotic wafer handler 136 may beconfigured to move a specimen to a stage within system 32 prior to orsubsequent to a lithography process or between steps of a lithographyprocess. Alternatively, a stage within system 32 may be configured tomove a specimen from system 32 to lithography tool 130. In an example,the stage may include a wafer handler configured to move a specimen fromsystem 32 to a process chamber of the lithography tool 130. Furthermore,the stage of system 32 may be configured to move the specimen from afirst process chamber to a second process chamber within lithographytool 130. System 32 may also be coupled to the stage such that system 32may move with the stage from a first process chamber to a second processchamber within lithography tool 130. In this manner, the system may beconfigured to determine at least two properties of a specimen as thespecimen is being moved from a first process chamber to a second processchamber of lithography tool 130. An example of an apparatus and a methodfor scanning a substrate in a processing system is illustrated inEuropean Patent Application No. EP 1 083 424 A2 to Hunter et al., and isincorporated by reference as if fully set forth herein.

In an embodiment, system 32 may be configured as an integrated stationplatform (“ISP”) system. A system may be configured as a stand-alonecluster tool. Alternatively, the ISP system may be coupled to a processtool. FIG. 14 illustrates a perspective view of an embodiment of ISPsystem 158 that may be arranged laterally proximate and coupled to asemiconductor fabrication process tool such as lithography tool 130. Inthis manner, ISP system 158 may be configured as a cluster tool coupledto lithography tool 130. For example, as shown in phantom in FIG. 13,ISP system 158 may be coupled to cassette end 160 of lithography tool130. FIG. 15 further illustrates a perspective view of an embodiment ofISP system 158 coupled to cassette end 160 of lithography tool 130. Asfurther shown in phantom in FIG. 13, ISP system 158 may be also coupledto interface system 152 at exposure tool end 162 of lithography tool130. ISP system 158 may be further configured as illustrated in U.S.Pat. No. 6,208,751 to Almogy, which is incorporated by reference as iffully set forth herein.

ISP system 158 may also be coupled to multiple process tools. Forexample, ISP system may be configured as a wafer buffer station betweena lithography tool and an etch tool. In this manner, the ISP system maybe configured to receive a specimen from the lithography tool subsequentto a lithography process and to send the specimen to an etch tool for anetch process. In addition, the ISP system may be configured to determineone or more properties of the specimen between the lithography and etchprocess. An example of a wafer buffer station is illustrated in PCTApplication No. WO 99/60614 to Lapidot, and is incorporated by referenceas if fully set forth herein. ISP system 158 may be further configuredas described by Lapidot.

ISP system 158 may include one or more measurement chambers. Forexample, the ISP system may have three measurement chambers 172, 174,176. A measurement device may be disposed within each measurementchamber. Each measurement device may be configured as described herein.The measurement chambers may be arranged in unit 160. Environmentalconditions within unit 160 may be controlled substantially independentlyfrom environmental conditions of the space surrounding ISP system 158.For example, environmental conditions within unit 160 such as relativehumidity, particulate count, and temperature may be controlled bycontroller computer 162 coupled to the ISP system. Such a unit may becommonly referred to as a “mini-environment.”

In addition, the one or more measurement chambers may be arranged suchthat first measurement chamber 172 may be located below secondmeasurement chamber 174 and such that second measurement 174 may belocated below third measurement chamber 176. In this manner, a lateralarea or “footprint” of the ISP system may be reduced. Furthermore,because ISP system 158 may be coupled to a semiconductor fabricationprocess tool, one front interface mechanical standard (“FIMS”) drop maybe coupled to both the semiconductor fabrication process tool and theISP system. As such, less FIMS drops may be required in a fabricationfacility (“fab”), and in particular a 300 mm wafer fab. A FIMS drop maybe a mechanical device configured to lower a FOUP from an overheadtransportation system to a semiconductor fabrication process tool or astand-alone inspection or metrology tool. An example of a specimentransportation system is illustrated in U.S. Pat. No. 3,946,484 toAronstein et al., and is incorporated by reference as if fully set forthherein.

In an embodiment, ISP system 158 may also include wafer handler 164,receiving station 166, sending station 168, and buffer cassette station170. Receiving station 166 and sending station 168 may be configuredsuch that a wafer handler of a semiconductor fabrication process toolmay move a specimen to the receiving station and from the sendingstation. Buffer cassette station 170 may be configured to hold a numberof specimens depending on, for example, the relative input and outputrates of a semiconductor fabrication process tool and ISP system 158.Receiving station 166 may also be configured to alter a position of aspecimen such that the specimen may be substantially aligned to ameasurement device coupled to one of the measurement chambers. Forexample, the receiving station may be configured to detect a positioningmark such as a notch or a flat on the specimen and to move the specimenlinearly and/or rotatably. Buffer cassette station 170 and receivingstation 166 may be further configured a buffer station as illustrated inU.S. Pat. No. 6,212,691 to Dvir, which is incorporated by reference asif fully described herein.

The ISP wafer handler may be configured to remove a specimen from thereceiving station. In addition, the ISP wafer handler may be furtherconfigured to move the specimen into one of the measurement chambers.Furthermore, the ISP wafer handler may be configured to move thespecimen into each measurement chambers in a sequence. In this manner,the ISP system may be configured to determine at least one property ofthe specimen in each of the plurality of measurement chambers in aparallel pipeline fashion.

In addition, the measurement device coupled to each measurement chambermay each be configured to determine a different property of a specimen.For example, a measurement device coupled to first measurement chamber172 may be configured to determine overlay misregistration of aspecimen. A measurement device coupled to second measurement chamber 174may be configured to determine a critical dimension of the specimen. Ameasurement device coupled to third measurement chamber 176 may beconfigured to determine a presence of macro defects on a surface of thespecimen. In alternative embodiments, a measurement device coupled toone of the measurement chambers may be configured to determine apresence of micro defects on a surface of the specimen or a thin filmcharacteristic of the specimen. A thin film characteristic may include athickness, an index of refraction, or an extinction coefficient asdescribed herein. Additionally, wafer handler 164 may be configured tomove the specimen from each measurement chamber to sending station 168.

Because ISP system 158 may be coupled to a semiconductor fabricationprocess tool such as lithography tool 130, properties of a specimen maybe determined faster than stand alone metrology and inspection tools.Therefore, a system, as described herein, may reduce theturn-around-time for determining properties of a specimen. A reducedturn-around-time may provide significant advantages for process control.For example, a reduced turn-around-time may provide tighter processcontrol of a semiconductor fabrication process than stand alonemetrology and inspection tools. Tighter process control may provide, forinstance, a reduced variance in critical dimension distributions offeatures on a specimen.

In addition, a system as described herein may be configured to adjust adrifting process mean to a target value and to reduce variance incritical dimension distribution of features on a specimen by accountingfor autocorrelation in the critical dimension data. For example, thecritical dimension distribution of features on a specimen after adevelop process step may be reduced by altering a parameter of aninstrument coupled to an exposure tool or a develop process chamber.Such an altered parameter may include, but is not limited to, anexposure dose of an exposure process or a develop time of a developprocess. In addition, a linear model of control may be used and only theoffset terms may be updated or adapted. A linear model of control mayinclude a control function such as: y=Ax+c, where A and c areexperimentally or theoretically determined control parameters, x is acritical dimension of the specimen or another such determined propertyof the specimen, and y is a parameter of an instrument coupled to thesemiconductor fabrication process tool. Alternatively, a parameter of aninstrument coupled to a semiconductor fabrication tool such as theexposure tool may be altered by using an exponentially weighted movingaverage of the offset terms. A proportional and integral model ofcontrol may include a control function such as:C_(t)=αE_(t-del)+(1−α)c_(t-1), wherein α is an experimentally ortheoretically determined control parameter, E_(t-del) is a determinedproperty of the specimen, and C_(t) is a parameter of an instrumentcoupled to the semiconductor fabrication process tool.

Variance in critical dimension distribution after develop may bedramatically reduced by a system as described herein. For example,adjusting a critical dimension mean to a target value of a lot (i.e.,25) of wafers using lot-to-lot feedback control may reduce criticaldimension variance by approximately 65%. In addition, lot-to-lotfeedback control may be effective if critical dimension within lotcritical dimensions are correlated. For example, low autocorrelation mayresult in no reduction of critical dimension variance using lot-to-lotfeedback control. High autocorrelation, however, may result in a 15%reduction of critical dimension variance using lot-to-lot feedbackcontrol. Controlling critical dimension variance using wafer-to-waferfeedback control, however, may be effective even if lot criticaldimensions are non correlated. For example, low autocorrelation mayresult in a 25% reduction in critical dimension variance usingwafer-to-wafer feedback control. Successful feedback control may dependon a proven APC frame work, robust process modeling, high throughputmetrology, efficient production methodology to reduce metrology delay,and enabling of process tool wafer based control. In addition, theeffect of turn-around-time on control of production wafers may also beexamined by using multiple lot averaged control to adjust drift in themean critical dimension. A target critical dimension may be set to beapproximately equal to the mean of the critical dimension data. As such,lot-to-lot control may result in an 8% improvement in critical dimensionvariance. In addition, wafer-to-wafer control may results in an 18%improvement in critical dimension variance.

FIG. 16 illustrates a schematic side view of an embodiment of system 32disposed within measurement chamber 178. For example, system 32 mayinclude stage 42 disposed within measurement chamber 178. In addition,system 32 may include measurement device 34 disposed within measurementchamber 178. Measurement chamber 178 may also include opening 179 and amechanical device (not shown) coupled to opening 179. In addition,measurement chamber 178 may include a plurality of such openings and amechanical device coupled to each of the openings. The mechanical devicemay be configured to place an object such as a thin sheet of metal infront of opening 179 and to remove the object from the opening. In thismanner, the mechanical device may be configured to provide access to themeasurement chamber, for example, when specimen 40 is being disposedupon stage 42 through opening 179. Specimen 40 may be disposed uponstage 42 by any of the methods or devices as described herein.Subsequent to disposing specimen 40 on stage 42, the object may beplaced in front of opening 179 by the mechanical device such thatenvironment conditions such as relative humidity, temperature, andparticulate count within the measurement chamber may be maintainedand/or controlled. In this manner, system 32 may be configured todetermine a property of specimen 40 under maintained and/or controlledenvironmental conditions, which may increase the reliability of thesystem. In addition, exposure of components of system 32 including, butnot limited to, measurement device 34 to environmental conditionsexternal to the measurement chamber may be reduced. As such,contamination and/or degradation of the components of system 32 may bereduced thereby reducing the probability of system failure, associatedmaintenance and repair costs, and increasing a lifetime of the system.

The system may also include processor 54 disposed outside of measurementchamber 178. In this manner, the processor, which may be configured as acontroller computer, may be accessed outside of the measurement chamber,for example, by an operator. In addition, arranging processor 54external to measurement chamber 178 may reduce the dimensions ofmeasurement chamber 178. By reducing the dimensions of measurementchamber 178, system 32 may be coupled to or disposed within a largernumber of process tools than a conventional metrology and/or inspectionsystem. For example, measurement chamber 178 may be configured to haveapproximately the same dimensions as a process chamber of asemiconductor fabrication process tool. In this manner, system 32 may bedisposed within an existing semiconductor fabrication process tool, asshown in FIG. 13, without altering an arrangement of the processchambers of the semiconductor fabrication process tool. For example,measurement chamber 178 may disposed within the tool by replacing one ofthe process chambers with measurement chamber 178. System 32 may befurther configured as described herein.

FIG. 17 illustrates a schematic side view of an embodiment ofmeasurement chamber 178 coupled to a process tool such as asemiconductor fabrication process tool. As shown in FIG. 17, measurementchamber 178 may be arranged laterally proximate to process chamber 180of a process tool. Alternatively, the measurement chamber may bearranged vertically proximate to process chamber 180. For example, themeasurement chamber may be arranged above or below process chamber 180.As shown in FIG. 17, process chamber 180 may be a resist apply chamberas described herein. For example, specimen 182 may be disposed uponstage 184. Stage 184 may be configured as a motorized rotating chuck orany other device known in the art. A resist may be dispensed ontospecimen 182 from dispense system 186. Dispense system 186 may becoupled to a resist supply and may include a number of pipes and/orhoses and controls such as valves such that resist may be transferredfrom the resist supply to specimen 182. The dispense system may also becoupled to a controller computer, which may be configured to control thedispense system. For example, the controller computer may includeprocessor 54 as described herein. Stage 184 may be configured to rotatesuch that the dispensed resist may spread over specimen 182 and suchthat solvent may evaporate from the dispensed resist. Process chamber180, however, may include any of the process chambers as describedherein. In addition, measurement chamber 178, process chamber 180, andprocessor 54 may be arranged in a modular architecture as illustrated inPCT Application No. WO 99/03133 to Mooring et al., which is incorporatedby reference as if fully set forth herein.

In an embodiment, therefore, specimen 182 may be easily and quicklymoved from process chamber 180 to measurement chamber 178 (or frommeasurement chamber 178 to process chamber 180) by a robotic waferhandler of a process tool, by a wafer handler of an ISP system, or bystage 42 as described herein. In this manner, system 32 may beconfigured to determine at least a first property and a second propertyof the specimen between process steps of a process. For example, in alithography process, first and second properties of a specimen may bedetermined subsequent to resist apply and prior to exposure. In anadditional example, first and second properties of a specimen may bedetermined subsequent to exposure and prior to post exposure bake. In afurther example, first and second properties of a specimen may bedetermined subsequent to post exposure bake and prior to develop. Firstand second properties of a specimen may also be determined subsequent todevelop. Furthermore, such a system may be configured to determine atleast a first property and a second property of the specimen prior tosubstantially an entire process or subsequent to substantially an entireprocess. A system configured as described above may also have arelatively short turn-around-time. As described above, therefore, such asystem may provide several advantages over currently used metrology andinspection systems.

A process tool such as a semiconductor fabrication process tool mayinclude a number of support devices such as stage 184, as shown in FIG.17, which may be configured to support the specimen during a processstep. For example, a support device may be disposed within each processchamber coupled to a process tool. Appropriate support devices mayinclude, but are not limited to, a spin coater, a bake plate, a chillplate, an exposure stage, and an electrostatic chuck in an etch ordeposition chamber. Each support device may have an upper surface uponwhich a specimen may be disposed. An upper surface of each supportdevice may be substantially parallel to an upper surface of othersupport devices arranged within the process tool, i.e., orientations ofeach support device within each process chamber, respectively, may besubstantially parallel. In an embodiment, a stage of a system, asdescribed herein, may also have an upper surface which may besubstantially parallel to an upper surface of a support device of theprocess tool, as shown in FIG. 17, i.e., an orientation of the stagewithin a measurement chamber such as measurement chamber 178 may besubstantially parallel to orientations of each support device withineach process chamber, respectively.

In an alternate embodiment, a stage of a system, as described herein,may have an upper surface that may be arranged at an angle with respectto an upper surface of a support device, i.e., an orientation of thestage within a measurement chamber may be at an angle to orientations ofeach support device within each process chamber, respectively. Forexample, an upper surface of the stage may be arranged at a 90° anglewith respect to an upper surface of a support device of a process tool.Alternatively, an upper surface of the stage may also be arranged at anangle of less than 90° with respect to an upper surface of the supportdevice. At such angles, a vacuum may be pulled on a surface of aspecimen to maintain a position of the specimen on the stage.

An orientation of a measurement device disposed within a measurementchamber with such a stage may also be altered. For example, themeasurement device may be arranged at an angle such that a spatialrelationship (i.e., any of the spatial arrangements shown in FIGS. 3-7,11 a-12, and 16-17) between the measurement device and the stage may bemaintained. Such a stage may also be arranged at an angle with respectto an illumination system and a detection system of the measurementdevice. In this manner, a specimen may be tilted with respect to themeasurement device during inspection or metrology processes which may beperformed by a system as described herein.

An angled orientation of the stage within a measurement chamber asdescribed above may allow a lateral dimension of the measurement chamberto be reduced. For example, the illumination system, the detectionsystem, and the stage may be arranged in a more compact geometry thanconventional inspection and metrology systems. In particular, a lateraldimension of a measurement chamber may be greatly reduced for relativelylarge diameter specimen such as 200 mm wafers and 300 mm wafers. Assuch, disposing such a measurement device within a semiconductorfabrication process tool may be less likely to require retrofitting ofthe semiconductor fabrication process tool. Therefore, existingconfigurations of semiconductor fabrication process tools may be lesslikely to prohibit disposing the system within the semiconductorfabrication process tool.

FIG. 18 illustrates a schematic side view of an embodiment of system 32coupled to process chamber 188. The process chamber may be a processchamber coupled to a semiconductor fabrication process tool. Stage 190may be disposed within process chamber 188. Stage 190 may be configuredto support specimen 192, for example, during a semiconductor fabricationprocess step. System 32 may be coupled to process chamber 188 such thatmeasurement device 34 may be external to process chamber 188 but may becoupled to stage 190 disposed within the process chamber. For example,process chamber 188 includes one or more relatively small sections 194of a substantially transparent material disposed within one or morewalls of the process chamber. Sections 194 may be configured to transmita beam of energy from an energy source of the measurement device outsidethe process chamber to a surface of a specimen within the processchamber. Sections 194 may also be configured to transmit a beam ofenergy returned from the surface of the specimen to a detector ofmeasurement device 34 outside process chamber 188. The substantiallytransparent material may have optical or material properties such thatthe beam of energy from the energy source and the returned beam ofenergy may pass through sections 194 of the process chamber withoutundesirably altering the properties of the directed and returned energybeams. For example, undesirably altering the properties of the energybeams may include, but is not limited to, altering a polarization or awavelength of the energy beams and increasing chromatic aberration ofthe energy beams. In addition, sections 194 may be configured such thatdeposition of process residue from a chemical using during processing ofa specimen may be reduced as described in PCT Application No. 99/65056to Grimbergen et al., which is incorporated by reference as if fully setforth herein.

An appropriate system and method for coupling a measurement deviceexternal to a process chamber and a stage disposed within the processchamber may vary, however, depending on, for example, a configuration ofthe process chamber and/or a configuration of the measurement device.For example, the placement and dimensions of relatively small section194 disposed within the walls of process chamber 188 may vary dependingon the configuration of the components within the process chamber. Assuch, exposure of measurement device 34 to chemicals and environmentalconditions within process chamber 188 may be reduced, and evensubstantially eliminated. Furthermore, measurement device 34 may beexternally coupled to process chamber 188 such that the measurementdevice may not alter operation, performance, or control of a processstep carried out in process chamber 188.

A measurement device, as shown in FIG. 18, may be configured to directenergy toward a surface of a specimen during a step of a process suchas, in an example of a lithography process as described above, during achill process subsequent to a post apply bake process, a post exposurebake process, a develop process, or any of the process steps asdescribed herein. In addition, the measurement device may be configuredto detect energy returned from the surface of the specimen during thestep of the process. The measurement device may be configured to detectenergy returned from a specimen substantially continuously or at varioustime intervals during a process step.

The system may include a processor configured to determine at least afirst and a second property of a specimen during a process step. Forexample, the processor may be configured to determine at least twoproperties of a specimen such as critical dimension and overlaymisregistration from the energy detected during a process step. In anadditional embodiment, the processor may also be configured to detectvariations in the energy detected by a measurement device during theprocess step. For example, the processor may be configured to obtain asignature characterizing the process step. The signature may include atleast one singularity representative of an end of the process step.

In an additional embodiment, the processor may also be coupled to aprocess tool such as a lithography tool and may be configured to alter aparameter of an instrument coupled to the process tool. For example, theprocessor may alter a parameter of an instrument coupled to a processtool in response to the detected singularity as described above. Theparameter of the instrument may be altered such that the process stepmay be terminated subsequent to detection of the singularity. Inaddition, the processor may be configured to alter a parameter of aninstrument of a process tool in response to at least one determinedproperty of the specimen using an in situ control technique.

In an additional embodiment, the processor may be configured to monitora parameter of an instrument coupled to a process tool such as asemiconductor fabrication process tool. For example, the processor maybe coupled to a resist apply process chamber of a lithography tool andmay be configured to monitor a parameter of an instrument coupled to theresist apply chamber. In this manner, the processor may be configured tomonitor a spin speed of a motorized chuck of the resist apply chamber, adispense time of a dispense system of the resist apply chamber, and/or atemperature and a humidity of the resist apply chamber. The processormay be further configured as described in an example of a method andapparatus for providing real-time information identifying tools visitedby a wafer under inspection and the process parameters used at thosetools illustrated in European Patent Application No. EP 1 071 128 A2 toSomekh, which is incorporated by reference as if fully set forth herein.In addition, the processor may be configured to determine a relationshipbetween at least one determined property of a specimen and a monitoredparameters of an instrument coupled to a process tool. For example, theprocessor may be configured to determine a relationship between apresence of defects on the surface of a resist layer formed on aspecimen and a monitored temperature and/or humidity of the resist applychamber. Furthermore, the processor may be configured to alter themonitored parameter of the instrument in response to the determinedrelationship. For example, the processor may be configured to use adetermined relationship to alter a parameter of an instrument coupled tothe resist apply chamber such that the temperature and humidity of theresist apply chamber may be altered in response to a determined presenceof defects on the surface of the specimen.

The processor may also be configured to alter a parameter of aninstrument coupled to a process tool in response to at least onedetermined property using a feedback control technique. Furthermore, theprocessor may also be configured to alter a parameter of an instrumentcoupled to a process tool in response to at least one determinedproperty using a feedforward control technique. For example, the systemmay be configured to determine at least two properties of a specimenduring a develop process. The processor may be configured to alter aparameter of an instrument coupled to the develop process chamber inresponse to at least one of the determined properties during developingof the specimen or prior to developing additional specimens. Inaddition, the processor may be configured to alter a parameter of aninstrument coupled to a process chamber such as a hard bake processchamber in response to at least one of the determined properties priorto further processing of the specimen in the process chamber. Inaddition examples, the processor may be configured to alter a parameterof an instrument coupled to an exposure tool, a post exposure bakechamber, a resist apply chamber, and any other tools or chamber includedin the cluster tool.

In a further embodiment, the processor may be configured to compare atleast one determined property of the specimen and properties of aplurality of specimens. For example, the plurality of specimens mayinclude product wafers processed prior to the processing of thespecimen. At least two properties of the plurality of specimens may bedetermined prior to processing of the specimen with a system asdescribed herein. The plurality of specimens may also include specimenswithin the same lot as the specimen or specimens within a different lotthan the specimen. As such, the processor may be configured to monitor aprocess such as a semiconductor fabrication process using awafer-to-wafer comparison technique or a lot-to-lot comparisontechnique. In this manner, the processor may be configured to monitorthe performance of the process and to determine if the performance ofthe process or a process tool is drifting. A method and apparatus forreducing lot to lot CD variation in semiconductor wafer processing isillustrated in European Patent Application No. EP 1 065 567 A2 to Su,and is incorporated by reference as if fully set forth herein.

Alternatively, the processor may be configured to compare at least onedetermined property of the specimen to a predetermined range for atleast the one property. The predetermined range may be determined, forexample, from design constraints for the specimen. In addition, thepredetermined range may be determined by using a statistical processcontrol method to determine an average of at least the one property andadditional statistical parameters such as a variance of at least the oneproperty for a process. In addition, the processor may be configured togenerate an output signal if at least the one determined property isoutside of a predetermined range. The output signal may be a visualsignal such as a signal displayed on a monitor coupled to the processor.The monitor may be disposed in a semiconductor fabrication facility suchthat the displayed signal may be viewed by an operator. Alternatively,the output signal may be any signal known in the art such as an audiblesignal or a plurality of signals.

In addition, subsequent to determining the property of the specimen, theprocessor may be configured to determine if additional processing of thespecimen may be performed. Additional processing of the specimen may bealtered or performed to alter the determined property. Such additionalprocessing may be commonly referred to as “reworking.” In this manner,the processor may be configured to make automated rework decisions. Forexample, such additional processing may include reprocessing thespecimen such that one or more process steps, which may have alreadybeen performed on the specimen, may be repeated. In addition, aparameter of one or more instruments coupled to one or more processchambers configured to perform the repeated process steps may be alteredin response to the determined property using a feedforward controltechnique. In this manner, such additional processing of the specimenmay be configured to alter the determined property by altering aparameter of the instrument in response to the determined property. Assuch, such additional processing may alter the determined property suchthat the determined property may be substantially equal to an expectedvalue for the property or may be within a predetermined range for theproperty.

In an additional embodiment, the processor may be configured to alter asampling frequency of a measurement device in response to at least onedetermined property of a specimen. For example, if a determined propertyis substantially different than an expected value for the property, orif a determined property is outside of a predetermined range for theproperty, then the processor may increase the sampling frequency of themeasurement device. The sampling frequency may be altered, for example,such that the measurement device is configured to direct and detectenergy from an increased number of locations on the specimen. In thismanner, the sampling frequency may be altered using an in situ controltechnique. In addition, the sampling frequency of the measurement devicemay be altered to determine statistical data of the determined propertyacross the specimen such as an average. As such, the determined propertymay be classified as a random defect, a repeating defect, or as anothersuch defect.

In an additional example, the sampling frequency of a measurement devicemay be altered such that subsequent measurement or inspection of thespecimen may be increased. In this manner, the sampling frequency may bealtered using a feedforward control technique. Subsequent measurement orinspection may include transferring the specimen to an additionalsystem, which may be configured as described herein, to further examinethe determined property of the specimen. An appropriate additionalsystem for such further examination of the determined property of thespecimen may include a system having a higher sensitivity, a highermagnification, and/or an increased resolution capability than the systemused to initially determine the property.

Alternatively, the sampling frequency may be altered such that themeasurement device is configured to direct and detect energy from anincreased number of locations on additional specimens that may be in thesame lot as the specimen. Furthermore, the sampling frequency may bealtered such that the measurement device is configured to direct anddetect energy from an increased number of specimens in the same lot asthe specimen or from a number of specimens in an increased number oflots. In this manner, the sampling frequency may be altered using afeedback control technique. As such, the sampling frequency may bealtered using an in situ control technique, a feedforward controltechnique, or a feedback control technique. In addition, each of thesecontrol techniques may be used to alter the sampling frequency of ameasurement device on a within-wafer basis, a within-lot basis, and/or alot-to-lot basis.

In a further embodiment, the processor may be configured to generate adatabase. The database may include a set of data that may include atleast first and second properties of a specimen. The processor may bealso be configured to calibrate the measurement device using thedatabase. For example, the set of data may include at least a first andsecond property of a reference specimen. The measurement device may beconfigured to determine the first and second properties of the referencespecimen. In this manner, the processor may be configured to calibratethe measurement device by comparing the first and second properties ofthe reference specimen in the database and the determined first andsecond properties of the reference specimen. For example, the processormay be configured to determine a correction factor from the comparisonof the first and second properties in the database and the determinedfirst and second properties of the reference specimen. In addition, theprocessor may be configured to use the correction factor to determinefirst and second properties of additional specimens.

In an additional embodiment, the processor may be configured to monitorthe measurement device using the database. For example, the database mayinclude at least two properties of a specimen. The system may beconfigured to determine at least the two properties of the specimen atpredetermined intervals of time. The processor may be configured tocompare at least the two properties of the specimen determined atdifferent times. As such, the processor may be configured to determineif the performance of the measurement device is changing over time. Inan additional example, the processor may be configured to generate a setof data that may include at least a first property and a seconddetermined property of a plurality of specimens at predetermined timeintervals. As such, the processor may also be configured to compare atleast the first and second properties of a plurality of specimens usingthe database. The first and second properties of a specimen or aplurality of specimens may be determined using the measurement device orusing a plurality of measurement devices. The processor may be furthercoupled to the plurality of measurement devices. Therefore, theprocessor may also be configured to calibrate the plurality ofmeasurement devices using the database as described above. In addition,the processor may also be configured to monitor the plurality ofmeasurement devices using the database as described above.

As described above, the processor may be coupled to a plurality ofmeasurement devices. In an additional embodiment, the processor may beconfigured to alter a parameter of an instrument coupled to at least oneof the plurality of measurement devices. Each of the measurement devicesmay be configured as a stand-alone metrology or inspection device.Alternatively, each of the measurement devices may be coupled to atleast one of a plurality of process tools as described herein.Furthermore, the processor may be coupled to at least one process tool.In this manner, the processor may be configured to alter a parameter ofan instrument coupled to at least one of the plurality of process tools.In addition, the processor may be configured to alter a parameter of aplurality of instruments. Each of the instruments may be coupled to oneof the plurality of process tools. The processor, however, may also beconfigured to alter a parameter of a plurality of instruments coupled toat least one of the plurality of process tools. For example, theprocessor may be configured to alter a parameter of the instrument inresponse to at least one of the determined properties using an in-situcontrol technique, a feedback control technique, and a feedforwardcontrol technique.

In an embodiment, the processor may include a local processor coupled tothe measurement device. The processor, however, may also include aremote controller computer or a remote controller computer coupled to alocal processor. The local processor may be configured to at leastpartially process a signal generated by the measurement device. Thesignal may be generated by the detection system and may be an analogsignal or a digital signal. For example, the system may also include ananalog-to-digital converter. The analog-to-digital converter may beconfigured to convert a signal generated by the detection system suchthat a digital signal may be sent to the local processor or the remotecontroller computer. In addition, the remote controller computer may beconfigured to further process the at least partially processed signal.For example, the local processor may be configured to determine at leasta first property and a second property of a specimen. In this manner,the remote controller computer may be configured to further process atleast the two determined properties. For example, further processing thedetermined properties may include comparing the determined properties toa predetermined range for each property. In addition, the remotecontroller computer may be configured to generate an output signal ifthe determined properties are outside of the predetermined range.

The processor may also take various forms, including, for example, apersonal computer system, mainframe computer system, workstation,network appliance, Internet appliance, personal digital assistant(“PDA”), television system, or other device. In general, the term“processor” may be broadly defined to encompass any device having aprocessor, which executes instructions from a memory medium. Examples ofprocessors and control methods are illustrated in U.S. Pat. No.4,571,685 to Kamoshida, U.S. Pat. No. 5,859,964 to Wang et al., U.S.Pat. No. 5,866,437 to Chen et al., U.S. Pat. No. 5,883,374 to Mathews,U.S. Pat. No. 5,896,294 to Chow et al., U.S. Pat. No. 5,930,138 to Linet al., U.S. Pat. No. 5,966,312 to Chen, U.S. Pat. No. 6,020,957 toRosengaus et al., and are incorporated by reference as if fully setforth herein. Additional examples of processors and control methods areillustrated in PCT Application Nos. WO 99/59200 to Lamey et al. and WO00/15870 to Putnam-Pite et al., and are incorporated by reference as iffully set forth herein.

FIG. 19 illustrates an embodiment of a method for determining at leasttwo properties of a specimen. As shown in step 196, the method mayinclude disposing a specimen upon a stage. The stage may be coupled to ameasurement device. The measurement device may be configured asdescribed herein. For example, the measurement device may include anillumination system and a detection system. As shown in step 198, themethod may include directing energy toward a surface of a specimen usingthe illumination system. In addition, the method may include detectingenergy propagating from the surface of the specimen, as shown in step200. Furthermore, the method may include processing the detected energyto determine at least a first property and a second property of aspecimen, as shown in step 202. The first property may include acritical dimension of the specimen. A critical dimension may include,but is not limited to, a lateral dimension of a feature of the specimen.A feature may be formed on an upper surface of the specimen or in thespecimen as described herein. The second property may include an overlaymisregistration of the specimen. Overlay misregistration may include alateral displacement of a first feature on a first level of a specimenwith respect to a second feature on a second level of a specimen. Thefirst level may be formed above the second level.

The stage may be configured as described herein. For example, the stagemay be configured to move laterally and rotatably. In this manner, themethod may include laterally or rotatably moving the stage. Laterally orrotatably moving the stage may include arranging the specimen such thatenergy from the measurement device may be directed to and may propagatefrom the specimen. The method may also include laterally and/orrotatably moving the stage while energy is being directed toward asurface of the specimen and while energy is being detected from thesurface of the specimen. As such, the method may include moving thestage laterally and/or rotatably during measurement or inspection of asurface of a specimen. In this manner, light may be directed to and maypropagate from a plurality of locations on a surface of the specimenduring measurement or inspection of a surface of the specimen. As such,the system may be configured to determine at least two properties of aspecimen at multiple locations on the specimen. In a further embodiment,the method may include rotating the stage while moving the measurementdevice linearly along a lateral dimension of a specimen as describedherein.

An illumination system of the measurement device may be configured asdescribed herein. In addition, a detection system of the measurementdevice may be configured as described herein. For example, themeasurement device may include, but is not limited to, a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, a spectroscopicellipsometer, bright field imaging device, a dark field imaging device,a bright field and dark field imaging device, a coherence probemicroscope, an interference microscope, and an optical profilometer. Inaddition, the measurement device may include any combination of theabove devices. As such, the measurement device may be configured tofunction as a single measurement device or as multiple measurementdevices. Because multiple measurement devices may be integrated into asingle measurement device of a system, optical elements of a firstmeasurement device, for example, may also be optical elements of asecond measurement device.

In an embodiment, the method may include processing the detected energyto determine a third property of the specimen. A third property of thespecimen may include, but is not limited to, a presence, a number, alocation, and/or a type of defects on the surface of the specimen and aflatness measurement of the specimen. The defects may include macrodefects and/or micro defects as described herein. In addition, themethod may include processing the detected energy to determine a thirdproperty and a fourth property of a specimen. For example, the thirdproperty may include a presence, a number, a location, and/or a type ofdefects on the surface of the specimen, and the fourth property mayinclude a flatness measurement of the specimen. As such, the method maybe used to determine a critical dimension, an overlay misregistration, apresence, a number, a location, and/or a type of defects on thespecimen, and a flatness measurement of the specimen. The method mayinclude determining such properties of a specimen sequentially orsubstantially simultaneously. In an additional embodiment, the methodmay include directing energy toward a front side and/or a back side of aspecimen. As such, the method may also include detecting energypropagating from the front side and/or the back side of the specimen,respectively. In this manner, the method may also include determining apresence, a number, a location, and/or a type of defects on a back sideof the specimen. The defects may include macro defects.

In an embodiment, the stage and measurement device may be coupled to aprocess tool such as a semiconductor fabrication process tool. Thesemiconductor fabrication process tool may include a lithography tool asdescribed herein. The stage and measurement device may be arrangedlaterally proximate to the process tool as described herein. Forexample, the stage and measurement device may be disposed within an ISPsystem as described above. Alternatively, the stage and the measurementdevice may be disposed within the process tool. For example, the stageand measurement device may be disposed within a measurement chamber. Themeasurement chamber may be coupled to the process tool. For example, themeasurement chamber may be arranged laterally proximate to a processchamber of the process tool. Alternatively, the measurement chamber maybe arranged vertically proximate to a process chamber of the processtool. The measurement chamber may be configured to isolate themeasurement device and the stage from environmental conditions withinthe process tool.

In an embodiment, a support device may be disposed within a processchamber of the process tool. The support device may be configured tosupport the specimen during a process step. For example, a supportdevice disposed within a resist apply chamber of a lithography tool mayinclude a chuck coupled to a motorized rotation device. As such, thesupport device may be configured to support the specimen during a resistapply process step of a lithography process. A support device may alsoinclude, for example, a bake plate disposed within a post apply bakechamber. The bake plate may be configured to support the specimen duringa post apply bake process step of the lithography process. An uppersurface of the support device may be substantially parallel to an uppersurface of the stage of the system. Alternatively, an upper surface ofthe stage may be angled with respect to an upper surface of the supportdevice. The stage may also be configured to hold a specimen in place atsuch an angle by drawing a vacuum through an upper surface of the stageor by an appropriate mechanical device. In this manner, a stage andmeasurement device may be substantially perpendicular to a supportdevice disposed within a process chamber. As such, the system may bearranged essentially on its “side.” The term “side,” as used herein,generally refers to a lateral sidewall of a conventional metrology orinspection system. The orientation of the stage with respect to asupport device of a process chamber may vary depending on, for example,the dimensions of a process tool and an arrangement of process chamberswithin the process tool. For example, the stage may be arranged at aperpendicular angle with respect to the support device such that themeasurement device and stage may be disposed within an existing processtool. In this manner, the system may be disposed within a process toolwithout reconfiguration of the process chambers.

In an additional embodiment, the process tool may include a waferhandler configured as described herein. For example, the wafer handlermay be configured to remove a specimen from a process chamber subsequentto a step of a process. The wafer handler may also be configured toplace a specimen into a process chamber prior to a step of a process. Inthis manner, the wafer handler may be configured to move the specimenfrom a first process chamber to a second process chamber between stepsof a process. Disposing the specimen upon the stage, as shown in step196, may include moving the specimen from the process tool to the stageusing the wafer handler. In addition, the method may include moving thespecimen to the process tool subsequent to directing energy toward asurface of the specimen and detecting energy propagating from a surfaceof the specimen. In this manner, the method may include determining atleast two properties of the specimen between process steps of a process.

In an alternative embodiment, the stage of the system may be disposedwithin a process chamber of the process tool. As such, the stage may beconfigured to function as a support device as described herein and maysupport the specimen during a process step. In this manner, disposingthe specimen upon a stage, as shown in step 196, may include disposingthe specimen upon a support device within a process chamber of a processtool. The method may also include directing energy toward a surface ofthe specimen and detecting energy propagating from the surface of thespecimen during a process step. In this manner, the system may beconfigured to determine at least two properties of a specimen atpredetermined time intervals during a process step. In an embodiment,the method may also include obtaining a signature characterizing aprocess step. The signature may include at least one singularity thatmay be representative of an end of the process step as described herein.Furthermore, the method may include altering a parameter of aninstrument coupled to a process tool in response to at least one of thedetermined properties using an in situ control technique.

In an embodiment, the stage and the measurement device may be coupled toa wafer handler of a process tool. The wafer handler may be configuredto support and move a specimen as described herein. In this manner, themethod may include directing energy toward a surface of the specimen anddetecting energy propagating from the surface of the specimen duringmovement of the specimen. As such, the method may also includedetermining at least two properties of a specimen while moving aspecimen from a first process chamber to a second process chamber. Inthis manner, the method may include determining at least two propertiesof a specimen between any two process steps of a process. For example,the method may include chilling the specimen in a first process chamber.In addition, the method may include applying resist to the specimen inthe second process chamber.

In additional examples, the method may include chilling the specimen ina first process chamber subsequent to a post apply bake process step.The method may also include exposing the specimen in the second processchamber. In a further example, the method may include chilling thespecimen in a first process chamber subsequent to a post exposure bakeprocess and developing the specimen in a second process chamber.Additionally, the method may include developing the specimen in a firstprocess chamber and baking the specimen in a second process chamber.Furthermore, the method may include developing the specimen in a firstprocess chamber and receiving the specimen in a wafer cassette in thesecond process chamber. In this manner, the method may includedetermining at least two properties of a specimen between any twoprocess steps of a semiconductor fabrication process.

In an alternative embodiment, the measurement device may be coupled to aprocess chamber such that moving the specimen to or from the processchamber may include moving the specimen under the measurement device. Inthis manner, the stage may include the wafer handler.

In an embodiment, the method may include comparing the determinedproperties of a specimen and determined properties of a plurality ofspecimens. For example, the method may include monitoring and evaluatinga semiconductor fabrication process using a wafer-to-wafer controltechnique. In addition, the method may include comparing properties of aspecimen determined at a first location on the specimen to properties ofthe specimen determined at a second location on the specimen. As such,the method may include monitoring and evaluating a semiconductorfabrication process using a within-wafer control technique.Alternatively, the method may also include comparing the determinedproperties of a specimen to a predetermined range for each property. Thepredetermined range may vary depending on, for example, designconstraints for each property such as an acceptable range of lateraldimensions for a feature on the specimen or an acceptable presence ofdefects on the surface of the specimen. The method may also includegenerating an output signal if the determined properties of the specimenare outside of the predetermined range for the property. The outputsignal may take various forms such as a visual signal and/or an audiblesignal. In addition, the output signal may be configured to indicatewhich of the determined properties is outside of the predetermined rangeand the extent to which the determined property is outside of thepredetermined range.

In an additional embodiment, the method may include altering a samplingfrequency of the measurement device in response to at least thedetermined first or second property of the specimen. For example, themethod may include increasing a sampling frequency of the measurementdevice in response to the determined properties. The sampling frequencymay be increased such that at least two properties may be determined atan increased number of locations on a single specimen. Alternatively,the sampling frequency may be increased such that at least twoproperties may be determined for an increased number of specimens suchas within a lot of wafers. In addition, the sampling frequency may beincreased such that at least two properties may be determined for anincreased number of lots.

In an embodiment, the method may also include altering a parameter of aninstrument coupled to a measurement device in response to at least oneof the determined properties of the specimen using a feedback controltechnique. For example, if a property of the specimen is determined tobe outside of a predetermined range, the method may include increasing asampling frequency of a measurement device prior to determining at leasttwo properties of additional specimens with the measurement device. Theadditional specimens may have been subjected to substantially the sameprocess step or process as the specimen having at least one propertyoutside of the predetermined range. In this manner, the method mayinclude sampling an increased number of specimens such that data may begenerated, which may be used to determine if the property of thespecimen outside of the predetermined range is occurring systematicallyor randomly.

In an additional embodiment, the method may include altering a parameterof an instrument coupled to a measurement device in response to at leastone of the determined properties of a specimen using a feedforwardcontrol technique. For example, the method may include determining atleast two properties of a specimen subsequent to a first process step ofa process using a measurement device. The method may also includedetermining at least two properties of a specimen subsequent to a secondprocess step of the process using the measurement device. If one of theproperties of the specimen determined after the first process step isoutside of the predetermined range, a sampling frequency of themeasurement device may be increased prior to determining at least twoproperties after the second process step. For example, the secondprocess step may include reprocessing the specimen or performing aprocess step of a process which has been altered in response to at leastone of the properties determined after the first process step. Forexample, the second process step may be configured to alter the propertyof the specimen such that the property may be within the predeterminedrange subsequent to the second process step. In this manner, the methodmay be used to determine if the second process step has altered theproperty of the specimen.

In an additional embodiment, the method may include generating adatabase. The database may include at least two determined properties ofa specimen. The method may also include calibrating the measurementdevice using the database. For example, the database may include atleast a first and second property of a reference specimen. In addition,the method may include determining the first and second properties ofthe reference specimen with the measurement device. In this manner, themethod may include calibrating the measurement device by comparing atleast one of the properties of the reference specimen in the databaseand at least one of the properties of the reference specimen determinedwith the measurement device. For example, the method may includedetermining a correction factor from the comparison of at least oneproperty of the reference specimen and using the correction factor todetermine at least the first and second properties of additionalspecimens.

In an additional embodiment, the method may include monitoring thedetermined properties generated by the measurement device using thedatabase. For example, the database may include at least two propertiesof a specimen. The method may also include determining at least the twoproperties of the specimen at predetermined intervals of time. In thismanner, the method may be include comparing at least the two propertiesof the specimen in the database to at least the two properties of thespecimen determined at various times. As such, the method may includedetermining if the performance of the measurement device is changingover time. In an additional example, the method may include generating adatabase that may include at least two properties of a plurality ofspecimens. At least the two properties of the plurality of specimens maybe determined using the measurement device. As such, the method mayinclude comparing at least one of the determined properties of aplurality of specimens using the database. Alternatively, the first andsecond properties of the plurality of specimens may be determined usinga plurality of measurement devices. Therefore, the method may alsoinclude calibrating the plurality of measurement devices using thedatabase as described above. In addition, the method may also includemonitoring the determined properties generated by the plurality ofmeasurement devices as described above. In an embodiment, the method mayalso include altering a parameter of an instrument coupled to each ofthe plurality of measurement devices in response to at least one of thedetermined properties of a specimen. Altering a parameter of aninstrument coupled to each of a plurality of measurement devices mayinclude any of the embodiments described herein.

In a further embodiment, the method may include altering a parameter ofan instrument coupled to a process tool such as a semiconductorfabrication process tool in response to at least one of the determinedproperties of the specimen using a feedback control technique. Forexample, the method may include altering a parameter of an instrumentcoupled to a lithography tool in response to a determined property asdescribed above. In addition, the method may include altering aparameter of an instrument in response to at least one of the determinedproperties of the specimen using an in situ control technique. Forexample, the method may include terminating a process step atapproximately a time that a singularity is detected by a measurementdevice.

Additionally, the method may also include altering a parameter of aninstrument coupled to a process tool in response to at least one of thedetermined properties using a feedforward control technique. Forexample, the method may include determining at least two properties of aspecimen during a develop process in a develop process chamber. Inaddition, the method may include altering a parameter of an instrumentcoupled to a process chamber in response to at least one of thedetermined properties prior to further processing of the specimen in theprocess chamber. In addition, the method may include altering aparameter of an instrument coupled to each of a plurality of processtools in response to at least one of the determined properties of thespecimen. Altering the parameter of an instrument coupled to each of aplurality of process tools may include any of the embodiments describedherein.

In an additional embodiment, the method may include monitoring aparameter of an instrument coupled to a process tool. For example, themethod may include monitoring a parameter of an instrument coupled to aresist apply chamber of a lithography tool. In this manner, the methodmay include monitoring a spin speed of a motorized chuck of the resistapply chamber, a dispense time of a dispense system of the resist applychamber, and/or a temperature and a humidity of the resist applychamber. In addition, the method may include determining a relationshipbetween a determined property of a specimen and the monitored parameterof an instrument. For example, the method may include determining arelationship between a presence of defects on the surface of a resistformed on a specimen and the temperature and/or humidity of the resistapply chamber. Furthermore, the method may include altering themonitored parameter of the instrument in response to the relationship.For example, the method may include using a determined relationship toalter a parameter of an instrument coupled to the resist apply chambersuch that the temperature and humidity of the resist apply chamber maybe altered in response to a determined presence of defects on thesurface of the specimen. In an additional embodiment, the method mayinclude altering a parameter of an instrument coupled to each of aplurality of process tools in response to at least one determinedproperty of the specimen. Altering a parameter of an instrument coupledto each of a plurality of process tools may include any of theembodiments as described herein.

In an additional embodiment, processing the detected energy may includeusing a processor to determine the first and second properties of aspecimen. The processor may be coupled to the measurement device. Themethod may, therefore, include sending a signal representative of thedetected energy to the processor. The processor may also be configuredas described in above embodiments. For example, the processor mayinclude a local processor coupled to a remote controller computer. Thelocal processor may be coupled to a measurement device as described inabove embodiments. FIG. 20 illustrates an embodiment of a method fordetermining at least two properties of a specimen. For example, as shownin step 202, the method may include processing the detected energy todetermine a first property and a second property of the specimen using aprocessor. As shown in step 206, processing the detected light may alsoinclude at least partially processing the detected energy using a localprocessor. The method may also include sending the partially processeddetected energy from the local processor to a remote controllercomputer, as shown in step 208. In addition, the method may furtherinclude further processing the at least partially processed detectedlight using the remote controller computer, as shown in step 210.

In an embodiment, at least partially processing the detected energy mayinclude determining at least two properties of a specimen. As such,further processing the detected energy may include processing thedetermined properties of the specimen. For example, processing thedetermined properties may include generating a database as described inabove embodiments. In addition, processing the determined properties mayinclude using at least one of the determined properties and arelationship between at least one property of the specimen and aparameter of an instrument coupled to a process tool to determine analtered parameter of the instrument. At least partially processing thedetected light and further processing the detected light may alsoinclude additional steps as described herein.

An embodiment also relates to a semiconductor device that may befabricated by a method, which may include any of the steps as describedherein. For example, an embodiment of a method for fabricating asemiconductor device is illustrated in FIG. 19. As shown in step 204,the method may include fabricating a portion of the semiconductor deviceon a specimen such as a wafer. Fabricating a portion of a semiconductordevice may include using a semiconductor fabrication process to processthe specimen. Appropriate semiconductor fabrication processes mayinclude, but are not limited to, lithography, etch, ion implantation,chemical vapor deposition, physical vapor deposition,chemical-mechanical polishing, and plating. In addition, fabricating aportion of the semiconductor device may include using a step of asemiconductor fabrication process to process the specimen.

In an embodiment, a method for fabricating a semiconductor device mayalso include disposing a specimen upon a stage, as shown in step 196. Inaddition, a method for fabricating a semiconductor device may furtherinclude directing energy toward a surface of the portion of thesemiconductor device formed on the specimen, as shown in step 198. Themethod may also include detecting energy propagating from a surface ofthe portion of the semiconductor device formed on the specimen, as shownin step 200. As further shown in step 202, the method may furtherinclude processing the detected light to determine at least twoproperties of the portion of the semiconductor device formed on thespecimen. Furthermore, a method for fabricating a semiconductor devicemay include any of the steps as described herein.

FIG. 21 illustrates an embodiment of a computer-implemented method forcontrolling a system to determine at least two properties of a specimen.In an embodiment, the system may include a measurement device. As shownin step 212, the method may include controlling the measurement device,which may include an illumination system and a detection system. Themeasurement device may be coupled to a stage. The measurement device mayfurther be configured as described herein. In addition, the method mayinclude controlling the illumination system to direct energy toward asurface of a specimen, as shown in step 214. The method may furtherinclude controlling the detection system to detect energy propagatingfrom the surface of the specimen, as shown in step 216. Furthermore, themethod may include processing the detected energy to determine at leasta first property and a second property of the specimen, as shown in step218. The first property may include a critical dimension of thespecimen. The critical dimension may include, but is not limited to, alateral dimension, a height, and/or a sidewall angle of a feature formedon a surface of the specimen. Alternatively, the critical dimension mayinclude a lateral dimension, a height, and/or a sidewall angle of afeature formed within a specimen. The second property may include anoverlay misregistration of the specimen.

In an embodiment, the method may also include controlling the stage,which may be configured to support the specimen. For example, the methodmay include controlling the stage to move the stage laterally,rotatably, or laterally and rotatably. The stage may be controlled tomove while the illumination system is directing energy toward thesurface of the specimen and while the detection system is detectingenergy propagating from the surface of the specimen.

In an additional embodiment, the method may also include processing thedetected energy to determine a third property of the specimen. Forexample, the third property may include a presence of defects on asurface of the specimen. The third property may also include a number, alocation, and/or a type of defects on a surface of the specimen. Thedefects may include micro defects, macro defects, or micro and macrodefects. In an embodiment, the method may also include controlling theillumination system to direct energy toward a back side of the specimen.The method may further include controlling the detection system todetect energy propagating from the back side of the specimen. As such,the third property of the specimen may also include a presence ofdefects on the back side of the specimen. Such defects may include macrodefects. In addition, a third property may also include a flatnessmeasurement of the specimen. In an additional embodiment, the method mayalso include processing the detected light to determine a third and afourth property of the specimen. In this manner, the third and fourthproperties may include, but are not limited to, a presence, a number, alocation, and/or a type of defects on a surface of the specimen and aflatness measurement of the specimen. In addition, the method mayinclude determining at least two of the properties substantiallysimultaneously. The method, however, may also include determining allfour of the properties described above sequentially or substantiallysimultaneously.

In an embodiment, the stage and the measurement device may be coupled toa process tool as described herein. For example, the stage andmeasurement device may be coupled to a lithography tool. The method mayalso include controlling a wafer handler of the process tool to move thespecimen from the process tool to the stage. The wafer handler may beconfigured as described herein. Alternatively, the method may includecontrolling the stage to move the specimen from the system to theprocess tool. In a further embodiment, the method may also includecontrolling the stage to move the specimen from a first process chamberto a second process chamber. The first and second process chambers maybe configured as described herein. In this manner, the method may alsoinclude controlling the illumination system to direct energy toward asurface of the specimen while the stage is moving the specimen from thefirst process chamber to the second process chamber. In addition, themethod may also include controlling the detection system to detectenergy propagating from the surface of the specimen while the stage ismoving the specimen from the first process chamber to the second processchamber. As such, the method may include determining at least twoproperties of the specimen between any two process steps of a process.

In an additional embodiment, the method may include controlling theillumination system to direct energy toward a surface of the specimenduring a process step. In addition, the method may also includecontrolling the detection system to detect energy propagating from thesurface of the specimen during the process step. As such, the method mayalso include processing the detected energy to determine at least twoproperties of the specimen at predetermined time intervals during theprocess step. In this manner, the method may also include controllingthe system to obtain a signature characterizing the process step. Thesignature may include at least one singularity, which may berepresentative of an end of the process step. In addition, the methodmay also include controlling the system to alter a parameter of aninstrument coupled to the process tool in response to the determinedproperties using an in situ control technique. Furthermore, thecomputer-implemented method may also include any of the steps asdescribed herein.

In an embodiment, a controller may be coupled to the system. Thecontroller may be a computer system configured to operate software tocontrol the system according to the above embodiments. The computersystem may include a memory medium on which computer programs may bestored for controlling the system and processing the detected energy.The term “memory medium” is intended to include an installation medium,e.g., a CD-ROM, or floppy disks, a computer system memory such as DRAM,SRAM, EDO RAM, Rambus RAM, etc., or a non-volatile memory such as amagnetic media, e.g., a hard drive, or optical storage. The memorymedium may include other types of memory as well, or combinationsthereof. In addition, the memory medium may be located in a firstcomputer in which the programs are executed, or may be located in asecond different computer that connects to the first computer over anetwork. In the latter instance, the second computer provides theprogram instructions to the first computer for execution. Also, thecomputer system may take various forms, including a personal computersystem, mainframe computer system, workstation, network appliance.Internet appliance, personal digital assistant (“PDA”), televisionsystem or other device. In general, the term “computer system” may bebroadly defined to encompass any device having a processor, whichexecutes instructions from a memory medium.

The memory medium may be configured to store a software program for theoperation of the system to determine at least two properties of aspecimen. The software program may be implemented in any of variousways, including procedure-based techniques, component-based techniques,and/or object-oriented techniques, among others. For example, thesoftware program may be implemented using ActiveX controls, C++ objects.JavaBeans, Microsoft Foundation Classes (“MFC”), or other technologiesor methodologies, as desired. A CPU, such as the host CPU, executingcode and data from the memory medium may include a means for creatingand executing the software program according to the methods describedabove.

Various embodiments further include receiving or storing instructionsand/or data implemented in accordance with the foregoing descriptionupon a carrier medium. Suitable carrier media include memory media orstorage media such as magnetic or optical media, e.g., disk or CD-ROM,as well as signals such as electrical, electromagnetic, or digitalsignals, conveyed via a communication medium such as networks and/or awireless link.

An embodiment relates to a system which may be configured to determineat least two properties of a specimen, which may include a presence ofdefects on the specimen and a thin film characteristic of the specimen.For example, a presence of defects may be determined on a front side ora back side of a specimen as described herein. The defects may alsoinclude subsurface defects and/or a presence of macro defects on abackside of a specimen, which may include copper contamination and/orresist contamination. In addition, the thin film characteristic mayinclude a thickness of a film such as copper. The system may beconfigured as described herein. In addition, the processor of such asystem may be configured to determine additional properties of thespecimen from energy detected by a measurement device. In an embodiment,the measurement device may be configured as a non-imaging scatterometer,a scatterometer, a spectroscopic scatterometer, a reflectometer, aspectroscopic reflectometer, an ellipsometer, a spectroscopicellipsometer, a bright field imaging device, a dark field imagingdevice, a bright field and dark field imaging device, a bright fieldnon-imaging device, a dark field non-imaging device, a bright field anddark field non-imaging device, a double dark field device, a coherenceprobe microscope, an interference microscope, an optical profilometer, adual beam spectrophotometer, a beam profile ellipsometer, or anycombination thereof. In this manner, the measurement device may beconfigured to function as a single measurement device or as multiplemeasurement devices. Because multiple measurement devices may beintegrated into a single measurement device of the system, opticalelements of a first measurement device, for example, may also be opticalelements of a second measurement device. Such a system may be coupled toa chemical-mechanical polishing tool, a deposition tool, an etch tool, acleaning tool such as a wet or dry stripping tool, or a thermal toolsuch as a furnace configured to perform rapid thermal processing (“RTP”)of a specimen as described herein. Examples of cleaning tools areillustrated in PCT Application No. WO 00/17907 and “Chemically AssistedLaser Removal of Photoresist and Particles from Semiconductor Wafers,”by Genut et al. of Oramir Semiconductor Equipment Ltd., Israel,presented at the 28^(th) Annual Meeting of the Fine Particle Society,Apr. 1-3, 1998, which are incorporated by reference as if fully setforth herein.

Spectroscopic ellipsometry may include focusing an incidence beam ofpolarized light on a specimen and monitoring a change in polarization ofat least a portion of the beam propagating from the specimen across abroad spectrum of wavelengths. Examples of spectroscopic ellipsometersare illustrated in U.S. Pat. No. 5,042,951 to Gold et al., U.S. Pat. No.5,412,473 to Rosencwaig et al., U.S. Pat. No. 5,581,350 to Chen et al.,U.S. Pat. No. 5,596,406 to Rosencwaig et al., U.S. Pat. No. 5,596,411 toFanton et al., U.S. Pat. No. 5,771,094 to Carter et al., U.S. Pat. No.5,798,837 to Aspnes et al., U.S. Pat. No. 5,877,859 to Aspnes et al.,U.S. Pat. No. 5,889,593 to Bareket et al., U.S. Pat. No. 5,900,939 toAspnes et al., U.S. Pat. No. 5,917,594 to Norton, U.S. Pat. No.5,973,787 to Aspnes et al., U.S. Pat. No. 6,184,984 to Lee et al., andare incorporated by reference as if fully set forth herein. Additionalexamples of spectroscopic ellipsometers are illustrated in PCTApplication No. WO 99/02970 to Rosencwaig et al. and is incorporated byreference as if fully set forth herein.

A measurement device configured as a spectroscopic ellipsometer mayinclude a polarizer, which may be coupled to the detection system. Abeam propagating from the specimen pass through the polarizer. Prior topassing through the polarizer, the returned beam may have ellipticalpolarization. After passing through the polarizer, the beam may belinearly polarized. The reflected light then pass through an analyzercoupled to the detection system and into a dispersion element, or aspectrometer. The dispersion element may be configured to separate beamcomponents having different wavelengths. The separated components of thebeam may be detected by individual elements of a detector array. Thepolarizer is usually rotating such that a time varying intensity may bedetected by the elements of the detector array.

A processor of the system may receive a signal responsive to thedetected light from each element of the detector array and may processthe signal as described herein. For example, an intensity of light ateach element of the detector array may be converted to ellipsometricparameters, ψ and Δ, by mathematical equations known in the art. Theellipsometric parameters may be typically shown as tan ψ and cos Δ. Tanψ is the amplitude of the complex ratio of the s and p components of thereflectivity of the sample, and Δ is the phase of the complex ratio ofthe s and p components of the reflectivity of the sample. The term “scomponent” is used to describe the component for the polarized radiationhaving an electrical field perpendicular to the plane of incidence ofthe reflected beam. The term “p component” is used to describe thecomponent for the polarized radiation having an electrical field in theplane of incidence of the reflected beam. For very thin films, tan ψ maybe independent of thickness, and Δ may be linearly proportional to thethickness.

Software integrated into the processor of the system may be configuredto convert the ellipsometric parameters, ψ and Δ, to an optical propertyof a specimen using a mathematical, or optical, model. Typically, apersonal computer having a software package operable to rapidlyperforming data-fitting calculations such as a least-squares fittingtechnique may be appropriate for this use. Because ellipsometricparameters including ψ and Δ may be determined at small incrementsacross a broad spectrum of wavelengths and at several angles, severalhundred data points may be included in the calculations. Severalsoftware packages configured for use with spectroscopic ellipsometersthat are capable of handling such a large amount of data arecommercially available. The processor that may be used to receive asignal responsive to the detected light from each element of thedetector array may be also used to perform the iterative data-fittingcalculations. Examples of such software packages may be incorporatedinto operating systems of spectroscopic ellipsometers, which have beenincluded by reference above, and are typically commercially available.

There are several optical models that may be used to analyzeellipsometric data. Examples, of such models include, but are notlimited to, a cauchy model, a harmonic oscillator model, and apolynomial series expansion model. An appropriate model, however, may bechosen based on specimen characteristics, desired optical properties ofthe specimen, and the computational difficulty associated with themodel. For example, the cauchy model is a relatively straightforwardmathematical model. The cauchy model, however, may not be valid forwavelengths at which a specimen exhibits absorption. Additionally,optical properties of several layers of a specimen may also bedetermined simultaneously by using an appropriate optical model or acombination of optical models. Therefore, when using spectroscopicellipsometry to analyze a specimen, one or more optical models may bemore appropriate for analysis than others.

Thicknesses, indexes of refraction, and extinction coefficients for alayer of a specimen, a portion of a layer of a specimen, or severallayers of a specimen may be determined from ellipsometric parametersusing an optical model. The index of refraction, “n,” is related to thespeed of light as it moves through a medium and is dependent upon thewavelength of the light. The extinction coefficient, “k,” is alsodependent upon wavelength and relates to absorption of light by amedium. The extinction coefficient may also be used to determine theabsorption coefficient for a given wavelength. Further discussion of theellipsometric parameters and the optical properties of materials isillustrated in U.S. Pat. No. 4,905,170 to Forouhi, et al. and isincorporated by reference as if fully set forth herein.

FIG. 22 illustrates an embodiment of a system configured to determine atleast two properties of a specimen coupled to chemical-mechanicalpolishing tool 222. Chemical-mechanical polishing (“CMP”) may typicallybe used in the semiconductor industry to partially remove or planarize alayer on a specimen. Chemical-mechanical polishing may include holdingand/or rotating a specimen against a rotating polishing platen undercontrolled pressure. Chemical-mechanical polishing tool 222 may includepolishing head 224 configured to hold specimen 226 against polishingplaten 228. Polishing head 224 may include a number of springs 230 oranother suitable mechanical device, which may be configured to apply anadjustable pressure to a back side of specimen 226. Polishing head 224may also be configured to rotate around a central axis of the polishinghead. In addition, polishing head 224 may also be configured to movelinearly with respect to the polishing platen.

Polishing platen 228 may also include a polishing pad 232. The polishingpad may have a back layer, which may be configured such that polishingpad 232 may be securely coupled to polishing platen 228. Polishing pad232 may also have an upper layer which may be configured to contact andpolish specimen 226. The upper layer of polishing pad 232 may include,for example, an open cell foamed polyurethane material or a polyurethanelayer having a grooved surface. The upper layer may also includeadditional abrasive materials or particles configured to partiallyremove or polish specimen 226. Polishing platen 228 may also beconfigured to rotate around a central axis of the polishing platen. Forexample, polishing platen 228 may be configured to rotate in a firstdirection, and polishing head 224 may be configured to rotate in asecond direction. The first direction may be substantially opposite tothe second direction.

Chemical-mechanical polishing tool 222 may also include dispense system234. The dispense system may be configured to automatically dispense apolishing chemical such as a chemical polishing slurry onto polishingpad 232. A chemical polishing slurry may include abrasive particles andat least one chemical. For example, abrasive particles may includefused-silica particles, and a chemical may include potassium hydroxide.Alternatively, polishing pad 232 may be sufficiently abrasive such thatthe chemical polishing solution may be substantially free of particles.Suitable combinations of a polishing chemical and a polishing pad mayvary depending on, for example, a composition and a topography of anupper layer on specimen 226 which is being partially removed orplanarized and/or a composition and a topography of an underlying layer.

A system configured to determine at least two properties of a specimenmay include measurement device 220 coupled to chemical-mechanicalpolishing tool 222. The measurement device may be configured accordingto any of the embodiments described herein. For example, measurementdevice 220 may be a non-imaging dark field device, a non-imaging brightfield device, a non-imaging dark field and bright field device, a doubledark field device, a dark field imaging device, a bright field imagingdevice, a dark field and bright field imaging device, a spectroscopicellipsometer, a spectroscopic reflectometer, a dual beamspectrophotometer, and a beam profile ellipsometer. In addition, themeasurement device may include any combination of the above devices. Assuch, the measurement device may be configured to function as a singlemeasurement device or as multiple measurement devices. Because multiplemeasurement devices may be integrated into a single measurement deviceof the system, optical elements of a first measurement device, forexample, may also be optical elements of a second measurement device.

The measurement device may be coupled to the chemical-mechanicalpolishing tool such that the measurement device may be external topolishing platen 228. In this manner, the measurement device may becoupled to chemical-mechanical polishing tool 222 such that themeasurement device may not interfere with the operation, performance, orcontrol of the chemical-mechanical polishing process. For example,polishing platen 228 and polishing pad 232 may be retrofitted such thata small section of a substantially optically transparent material 236may be disposed within the polishing platen and the polishing pad. Theconfiguration of the chemical-mechanical polishing tool, however, maydetermine the placement and dimensions of the transparent materialsection 236.

The small section of transparent material 236 may transmit an incidentbeam of light from a light source of measurement device 220 outside thepolishing platen to a surface of specimen 226 held in place by polishinghead 224 and light propagating from a surface of specimen 226 to adetector of measurement device 220 external to the polishing platen. Theoptically transparent material 236 may have optical or materialproperties such that light from a light source of measurement device 220and light propagating from a surface of specimen 226 may pass throughthe transparent sections of the polishing platen and the polishing padwithout undesirably altering the properties of the incident and returnedlight beams.

Polishing chemicals such as chemical-polishing slurries, however, mayinclude abrasive particles, chemicals, and material removed from thespecimen, which may interfere with light from the light source and lightpropagating from a surface of the specimen. In an embodiment, therefore,the section of transparent material 236 may be configured to function asa self-clearing objective. The self-clearing objective may include anoptical component configured to transmit light from a light sourcetoward a surface of specimen 226. A self-clearing objective may also beconfigured to flow a substantially transparent fluid between theself-clearing objective and the specimen. The flowing fluid may beconfigured to remove abrasive particles, chemicals, and material removedfrom the specimen such that light may be transmitted from themeasurement device to the specimen and from the specimen to a detectorof the measurement device without undesirable alterations in the opticalproperties of the light. Examples of self-clearing objectives areillustrated in U.S. patent application Ser. No. 09/396,143, “Apparatusand Methods for Performing Self-Clearing Optical Measurements,” toNikoonahad et al., issued as U.S. Pat. No. 6,628,397 on Sep. 30, 2003,and Ser. No. 09/556,238, “Apparatus and Methods for Detecting KillerParticles During Chemical Mechanical Polishing,” to Nikoonahad et al.,issued as U.S. Pat. No. 6,671,051 on Dec. 30, 2003, and are incorporatedby reference as if fully set forth herein. In this manner, themeasurement device may be coupled to a stage (i.e., polishing platen228) disposed within the process chamber and configured to support thespecimen.

Examples of chemical-mechanical polishing systems and methods areillustrated in U.S. Pat. No. 5,730,642 to Sandhu et al., U.S. Pat. No.5,872,633 to Holzapfel et al., U.S. Pat. No. 5,964,643 to Birang et al.,U.S. Pat. No. 6,012,966 to Ban et al., U.S. Pat. No. 6,045,433 to Dviret al., U.S. Pat. No. 6,159,073 to Wiswesser et al., and U.S. Pat. No.6,179,709 to Redeker et al., and are incorporated by reference as iffully set forth herein. Additional examples of chemical-mechanicalpolishing systems and methods are illustrated in PCT Application Nos. WO99/23449 to Wiswesser, WO 00/00873 to Campbell et al., WO 00/00874 toCampbell et al., WO 00/18543 to Fishkin et al., WO 00/26609 to Wiswesseret al., and WO 00/26613 to Wiswesser et al., and European PatentApplication Nos. EP 1 022 093 A2 to Birang et al. and EP 1 066 925 A2 toZuniga et al., and are incorporated by reference as if fully set forthherein. An additional example of an integrated manufacturing toolincluding electroplating, chemical-mechanical polishing, clean and drystations is illustrated PCT Application No. WO 99/25004 to Sasson etal., and is incorporated by reference as if fully set forth herein.

An embodiment relates to a system that may be configured to determine atleast two properties of a specimen including a presence of defects on aspecimen and a critical dimension of the specimen. The system may beconfigured as described herein. For example, the system may include aprocessor coupled to a measurement device and configured to determine atleast a presence of defects and a critical dimension of the specimenfrom one or more output signals of the measurement device. In addition,the processor may be configured to determine other properties of thespecimen from the one or more output signals. In an embodiment, themeasurement device may include a non-imaging scatterometer, ascatterometer, a spectroscopic scatterometer, a reflectometer, aspectroscopic reflectometer, an ellipsometer, a spectroscopicellipsometer, a bright field imaging device, a dark field imagingdevice, a bright field and dark field imaging device, a bright fieldnon-imaging device, a dark field non-imaging device, a bright field anddark field non-imaging device, a coherence probe microscope, aninterference microscope, an optical profilometer, or any combinationthereof. Such a system may be coupled to a process tool such as alithography tool, an etch tool, a deposition tool, or a plating tool asdescribed herein.

In an embodiment, a system configured to determine at least a presenceof defects on a specimen and a critical dimension of the specimen may becoupled to an etch tool as described herein. The presence of defects mayinclude a presence of defects on a back side of the specimen. Inaddition, the system may be further configured to determine a number, alocation, and/or a type of defects on the specimen. The system may becoupled to the etch tool such that at least a presence of defects on thespecimen and a critical dimension of the specimen may be determinedprior to and subsequent to an etch process or a step of an etch process.As described herein, at least one of the determined properties may beused to alter a parameter of one or more instruments coupled to aprocess tool. For example, a determined critical dimension of thespecimen may be used to alter a parameter of one or more instrumentscoupled to a lithography tool using a feedforward control technique or afeedback control technique. In addition, a determined presence ofdefects on the specimen may be used to alter a parameter of one or moreinstruments coupled to the lithography tool using a feedforward controltechnique or a feedback control technique.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including a critical dimension of the specimenand a thin film characteristic of the specimen. The system may beconfigured as described herein. For example, the system may include aprocessor coupled to a measurement device. The processor may beconfigured to determine at least a critical dimension and a thin filmcharacteristic of the specimen from one or more output signals generatedby the measurement device. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a photo-acoustic device, agrazing X-ray reflectometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, a dual beam spectrophotometer, a beam profileellipsometer, or any combination thereof. Such a system may be coupledto a process tool such as a lithography tool, an etch tool, a depositiontool, or a plating tool as described herein.

In addition, a system configured to determine at least a criticaldimension and a thin film characteristic of a specimen may be coupled toa chemical-polishing tool. For example, the processor may be configuredto determine a critical dimension of a feature on the specimen from oneor more output signals from a non-imaging scatterometer, ascatterometer, or a spectroscopic scatterometer. In addition, theprocessor may be configured to determine a thickness of a layer on thespecimen from one or more output signals from a reflectometer, aspectroscopic reflectometer, an ellipsometer, a spectroscopicellipsometer, a photo-acoustic device, and/or a grazing X-rayreflectometer. For example, an ellipsometer or a spectroscopicellipsometer may be configured to generate one or more output signalsresponsive to a thickness of metal and semi-metallic layers havingrelatively thin thicknesses and relatively thick transparent layers. Aphoto-acoustic device may be configured to generate one or more outputsignals responsive to a thickness of relatively thin metal layers, and agrazing X-ray reflectometer may be configured to generate one or moreoutput signals responsive to relatively thick and relatively thinlayers. In this manner, a system, as described herein, may be configuredto determine a thickness of layers having a broad range of thicknessesand materials.

The system may be coupled to a chemical-mechanical polishing toolaccording to any of the embodiments described herein. For example, themeasurement device may be coupled to a polishing pad of achemical-mechanical polishing tool such that the system may determine atleast two properties of a specimen disposed upon the polishing pad.Alternatively, the measurement device may be coupled to achemical-mechanical polishing tool such that the system may determine atleast two properties of a specimen being disposed upon or removed fromthe polishing pad. For example, the measurement device may be coupled toa chemical-mechanical polishing tool such that a robot wafer handler maymove below or above the measurement device. In an alternativeembodiment, the measurement device may be coupled to a robotic waferhandler of a chemical-mechanical polishing tool. In this manner, thesystem may be configured to determine at least two properties of thespecimen as the robotic wafer handler is moving the specimen.

In a further embodiment, the measurement chamber may be coupled to anddisposed laterally or vertically proximate an exit chamber of achemical-mechanical polishing tool. An exit chamber of achemical-mechanical polishing tool may include a water bath configuredto receive a specimen subsequent to a chemical-mechanical polishingprocess. The water bath may be used to remove chemicals, slurryparticles, and/or specimen particles remaining on the specimensubsequent to a chemical-mechanical polishing process. In this manner,the system may be configured to determine at least two properties of thespecimen as the specimen is disposed within or moving through the exitchamber.

In an additional embodiment, the measurement device may be disposed in ameasurement chamber, as described with respect to and shown in FIG. 16.The measurement chamber may be coupled to a chemical-mechanicalpolishing tool, as shown in FIG. 17. For example, the measurementchamber may be disposed laterally or vertically proximate one or morepolishing chambers of a chemical-mechanical polishing tool. In addition,the measurement chamber may be disposed laterally or verticallyproximate a load chamber of a chemical-mechanical polishing tool. A loadchamber of a chemical-mechanical polishing tool may be configured tosupport multiple specimens such as a cassette of wafers that are to beprocessed in the chemical-mechanical polishing tool. A robotic waferhandler may be configured to remove a specimen from the load chamberprior to processing and to dispose a processed specimen into the loadchamber. Furthermore, the measurement chamber may be disposed in otherlocations proximate a chemical-mechanical polishing tool such asanywhere proximate the chemical-mechanical polishing tool where there issufficient space for the system and anywhere a robotic wafer handler mayfit such that a specimen may be moved between a polishing pad and thesystem.

In an additional embodiment, a system may be configured to determine atleast three properties of a specimen including a critical dimension ofthe specimen, a presence of defects on the specimen, and a thin filmcharacteristic of the specimen. The defects may also include subsurfacedefects and/or a presence of macro defects on a backside of a specimen,which may include, but are not limited to, copper contamination and/orresist contamination. In addition, the thin film characteristic mayinclude a thickness of a film such as copper. The system may beconfigured as described herein. For example, the system may also includea processor coupled to a measurement device and configured to determineat least a critical dimension, a presence of defects, and a thin filmcharacteristic of the specimen from one or more output signals generatedby the measurement device. In addition, the processor may be configuredto determine other properties of the specimen from the one or moreoutput signals. In an embodiment, the measurement device may include anon-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a bright field imagingdevice, a dark field imaging device, a bright field and dark fieldimaging device, a bright field non-imaging device, a dark fieldnon-imaging device, a bright field and dark field non-imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, a dual beam spectrophotometer, a beam profileellipsometer, or any combination thereof. Such a system may be coupledto a process tool such as a lithography tool, an etch tool, a depositiontool, or a plating tool as described herein.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including a presence of macro defects on thespecimen and a presence of micro defects on the specimen. The system maybe configured as described herein. For example, the system may include aprocessor coupled to a measurement device. The processor may beconfigured to determine at least a presence of macro defects and apresence of micro defects on the specimen from one or more outputsignals generated by the measurement device. In addition, the processormay be configured to determine other properties of the specimen from theone or more output signals. For example, the processor may be configuredto determine a presence of subsurface defects such as voids from one ormore output signals generated by a measurement device such as an e-beamdevice, an X-ray reflectometer, or an X-ray fluorescence device. Suchvoids may be problematic, in particular for copper structures, if thevoids fill with chemicals such as plating solutions, which may corrodethe metal. In addition, the processor may be configured to determine athickness of a metal layer such as copper on the specimen from one ormore output signals generated by a measurement device such as an X-rayreflectometer and/or an X-ray fluorescence device.

Furthermore, the processor may be configured to determine a presence ofmacro defects on a backside of a specimen from one or more outputsignals generated by a measurement device such as an opticalfluorescence device. The macro defects may include copper contaminationand/or resist contamination. An optical fluorescence device may beconfigured to direct a beam of light to a surface of a specimen toinduce fluorescence of the specimen. The directed beam of light may havea wavelength of approximately 364 nm. The wavelength of the directedbeam of light may vary, however, depending upon, for example, a materialthat may be a defect. The optical fluorescence device may be furtherconfigured to detect fluorescence of the specimen and to generate one ormore output signals in response to the detected fluorescence. Aprocessor may be configured to determine a presence of macro defects,for example, by comparing detected fluorescence at multiple points onthe specimen.

In an embodiment, the measurement device may include a non-imagingscatterometer, a scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, a brightfield non-imaging device, a dark field non-imaging device, a brightfield and dark field non-imaging device, a double dark field device, acoherence probe microscope, an interference microscope, an opticalprofilometer, an e-beam device such as a scanning electron microscope ora tunneling electron microscope, an X-ray reflectometer, an X-rayfluorescence device, an optical fluorescence device, an eddy currentimaging device, and a relatively large-spot e-beam device, or anycombination thereof. For example, an appropriate combination may includean eddy current imaging device and a relatively large-spot e-beamdevice. An eddy current imaging device may generate one or more outputsignals that may be used as a qualitative excursion monitor for apresence of macro defects on a surface of the specimen. The eddy currentimaging device may be configured as described herein. A large-spote-beam device such as a scanning electron microscope may have relativelylow resolution and a relatively low data rate. One or more outputsignals generated by such an e-beam device may include a voltagecontrast that may vary depending upon a presence of defects such asmacro defects on the surface of the specimen. An example of an e-beamdevice is illustrated in U.S. patent application Ser. No. 09/882,804entitled “Sectored Magnetic Lens,” by John A. Notte IV, filed on Jun.15, 2001, issued as U.S. Pat. No. 6,515,287 on Feb. 4, 2003, which isincorporated by reference as if fully set forth herein.

Such a system may be coupled to any of the process tools as describedherein. For example, the system may be coupled to a lithography tool oran etch tool as described herein.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including a presence of macro defects on atleast one surface of the specimen and overlay misregistration of thespecimen. The determined properties may also include a number, alocation, and a type of macro defects present on at least one surface ofthe specimen. At least one surface of the specimen may include a backside and/or a front side of the specimen. The system may be configuredas described herein. For example, the system may include a processorcoupled to a measurement device. The processor may be configured todetermine at least a presence of macro defects and overlaymisregistration of the specimen from one or more output signalsgenerated by the measurement device. In addition, the processor may beconfigured to determine other properties such as a critical dimension ofa feature on the specimen from the one or more output signals. In anembodiment, the measurement device may include a scatterometer, anon-imaging scatterometer, a spectroscopic scatterometer, areflectometer, a spectroscopic reflectometer, an ellipsometer, aspectroscopic ellipsometer, a beam profile ellipsometer, a bright fieldimaging device, a dark field imaging device, a bright field and darkfield imaging device, a bright field non-imaging device, a dark fieldnon-imaging device, a bright field and dark field non-imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, or any combination thereof.

Such a system may be coupled to any of the process tools as describedherein. For example, the system may be coupled to a process tool such asa lithography tool, an etch tool, and a deposition tool. The system maybe coupled to the process tool according to any of the embodiments asdescribed herein. For example, the measurement device may be coupled toa process chamber of the process tool such that the system may determineat least two properties of a specimen disposed within the processchamber. Alternatively, the measurement device may be coupled to aprocess chamber of the process tool such that the system may determineat least two properties of a specimen being disposed within or removedfrom the process chamber. For example, the measurement device may becoupled to the process chamber such that a robot wafer handler may movebelow or above the measurement device. In an alternative embodiment, themeasurement device may be coupled to a robotic wafer handler of theprocess tool. In this manner, the system may be configured to determineat least two properties of the specimen as the robotic wafer handler ismoving the specimen.

In an additional embodiment, the measurement device may be disposed in ameasurement chamber, as described with respect to and shown in FIG. 16.The measurement chamber may be coupled to the process tool, as shown inFIG. 17. For example, the measurement chamber may be disposed laterallyor vertically proximate one or more process chambers of the processtool. For example, the deposition tool may include a cluster of processchambers that may each be configured to perform substantially similarprocesses or different processes. In addition, the measurement chambermay be disposed laterally or vertically proximate a load chamber of theprocess tool. A load chamber of a deposition tool may be configured tosupport multiple specimens such as a cassette of wafers that are to beprocessed in the process tool. A robotic wafer handler may be configuredto remove a specimen from the load chamber prior to processing and todispose a processed specimen into the load chamber. Furthermore, themeasurement chamber may be disposed in other locations proximate aprocess tool such as anywhere proximate the process tool where there issufficient space for the system and anywhere a robotic wafer handler mayfit such that a specimen may be moved between a process chamber and thesystem.

In addition, a parameter of one or more instruments coupled to a processtool may be altered in response to the properties determined by thesystem using a feedback control technique, an in situ control technique,and/or a feedforward control technique. For example, a presence of macrodefects on the surface such as a presence of macro defects on a backside of a specimen determined by the system prior to, during, and/orsubsequent to an etch process, a deposition process, and/or achemical-mechanical process may be used to alter a parameter of one ormore instruments coupled to a lithography tool using a feedforwardcontrol technique. In this example, the determined presence of macrodefects on the back side of the specimen may be used to alter a dose andfocus condition of an exposure tool during exposure of the specimenduring a lithography process. In an additional example, overlaymisregistration of a specimen determined by the system prior to, during,and/or subsequent to an etch process and/or a deposition process may beused to alter a parameter of one or more instruments coupled to alithography tool using a feedforward control technique. In this example,the determined overlay misregistration may be used to alter a lateralalignment of a reticle in an exposure tool during exposure of thespecimen during a lithography process.

A deposition tool may be configured for chemical vapor deposition, asdescribed below, or for physical vapor deposition. Physical vapordeposition may commonly be used in the semiconductor industry to form alayer of a conductive material upon a specimen such as a wafer. Aphysical vapor deposition tool may include a vacuum process chamber inwhich argon ions may be generated. In addition, a support device may bedisposed within the process chamber. The support device may beconfigured to support a specimen during a physical vapor depositionprocess. In addition, a circular-shaped metal target may be disposedabove the support device. The physical vapor deposition tool may alsoinclude an annular metal coil interposed between the support device andthe metal target. The annular metal coil may be made of the samematerial as the metal target. A physical vapor deposition tool may alsoinclude a voltage controller configured to supply a voltage to the metaltarget, the metal coil, and the support device. The voltage controllermay be further configured to generate voltage biases between the metaltarget and the support device and between the support device and themetal coil. The voltage biases may cause argon ions to bombard the metaltarget and the metal coil to release metal atoms, which may then sputteronto a surface of a specimen on the support device. Examples of physicalvapor deposition systems and methods are illustrated in U.S. Pat. No.5,754,297 to Nulman, U.S. Pat. No. 5,935,397 to Masterson, U.S. Pat. No.6,039,848 to Moslehi et al., U.S. Pat. No. 6,080,287 to Drewery et al.,and U.S. Pat. No. 6,099,705 to Chen et al., and are incorporated byreference as if fully set forth herein.

A system, as described herein, may be coupled to a physical vapordeposition tool. For example, the system may be disposed within ameasurement chamber. The measurement chamber may be configured asdescribed herein. The measurement chamber may be located proximate aprocess chamber of the physical vapor deposition tool. Alternatively,the system may be coupled to a process chamber of the physical vapordeposition tool. In this manner, the system may be integrated into aphysical vapor deposition tool. As such, the system may be configured todetermine at least two properties of a specimen prior to, during, orsubsequent to a physical vapor deposition process. Such arrangements ofa system and a process chamber are described with reference to andillustrated in, for example, FIGS. 17 and 18. Process chambers 180 and188, as illustrated in FIGS. 17 and 18, may be configured differentlythan shown such that the process chamber may be configured for aphysical vapor deposition process. For example, process chamber 180 maynot include dispense system 186 and, instead, may include variousdevices and components as described above. Furthermore, a system may becoupled to a wafer handler of a physical vapor deposition tool.Therefore, the system may be configured to determine at least twoproperties of a specimen while the specimen is being moved into aprocess chamber or out of a process chamber of a physical vapordeposition tool.

Plating may commonly be used in the semiconductor industry to form alayer of metal upon a specimen such as a wafer. A plating tool mayinclude a process chamber such as a plating bath. A plurality of supportdevices may be disposed within the plating bath. Each of the supportdevices may be configured to support a specimen during a platingprocess. The plating tool may also include a cathode electrode arrangedabove and in contact with an upper surface of a specimen. In addition,the plating tool may include an anode electrode located beneath thespecimen. A plating solution may flow into the plating bath from aninlet port and may be ejected upwardly onto a surface of a specimen.Furthermore, the plating tool may include a heater configured to heatthe plating solution during a plating process. Controlling thetemperature of the plating solution may be critical to forming a metallayer without defects such as structural changes, hardening, and/orplating burn of the layer. In addition, characteristics of a metal layerformed on a specimen may vary depending on additional characteristics ofthe plating solution. For example, the characteristics of a layer ofplated metal may depend on a metal ion concentration in the platingsolution, the pH level of the plating solution, and the specific gravityof the plating solution. An example of a system and a method for platingspecimens is illustrated in U.S. Pat. No. 5,344,491 to Katou, and isincorporated by reference as if fully set forth herein.

As described herein, a system may be coupled to a plating tool. Forexample, the system may be disposed within a measurement chamber. Themeasurement chamber may be configured as described herein. Themeasurement chamber may be located proximate a process chamber of theplating tool. Alternatively, the system may be coupled to a processchamber of the plating tool. Therefore, the system may be configured todetermine at least two properties of a specimen prior to, during, orsubsequent to a plating process. Such arrangements of a system and aprocess chamber are described with reference to and illustrated in, forexample, FIGS. 17 and 18. Process chambers 180 and 188, as illustratedin FIGS. 17 and 18, may be configured differently than shown such thatthe process chamber may be configured for a plating process. Forexample, process chamber 180 may not include dispense system 186 and,instead, may include various devices and components as described above.In addition, a system may be coupled to a wafer handler of a platingtool as described herein. As such, a system may be configured todetermine at least two properties of a specimen while a specimen isbeing disposed within or removed from a process chamber of a platingtool.

An embodiment relates to a system which may be configured to determineat least a flatness measurement of the specimen, a presence of defectson the specimen, and a thin film characteristic of a specimen. Thedefects may include subsurface defects and/or a presence of macrodefects on a backside of a specimen, which may include, but are notlimited to, copper contamination and/or resist contamination. Inaddition, the thin film characteristic may include a thickness of a filmsuch as copper. The system may be configured as described herein. Forexample, the system may include a processor coupled to a measurementdevice. The processor may be configured to determine at least a flatnessmeasurement of the specimen, a presence of defects on the specimen, anda thin film characteristic of a specimen from one or more output signalsgenerated by the measurement device. In addition, the processor may beconfigured to determine other properties of the specimen from the one ormore output signals. In an embodiment, the measurement device mayinclude a non-imaging scatterometer, a scatterometer, a spectroscopicscatterometer, a reflectometer, a spectroscopic reflectometer, anellipsometer, a spectroscopic ellipsometer, a bright field imagingdevice, a dark field imaging device, a bright field and dark fieldimaging device, a bright field non-imaging device, a dark fieldnon-imaging device, a bright field and dark field non-imaging device, adouble dark field device, a coherence probe microscope, an interferencemicroscope, an interferometer, an optical profilometer, a dual beamspectrophotometer, a beam profile ellipsometer, or any combinationthereof. In this manner, the measurement device may be configured tofunction as a single measurement device or as multiple measurementdevices.

Such a system may be coupled to a chemical-mechanical polishing tool asdescribed above. In this manner, the system may be configured todetermine at least the three properties of a specimen prior to, during,or subsequent to a chemical-mechanical polishing process. Alternatively,such a system may be disposed within a measurement chamber, which may beconfigured as described herein. The measurement chamber may be locatedproximate the chemical-mechanical polishing tool. Therefore, such asystem may be configured to determine at least the three properties ofthe specimen prior to or subsequent to a chemical-mechanical polishingprocess. Therefore, the flatness measurement of a specimen may include ameasure of stress-induced curvature of a specimen due to achemical-mechanical polishing process. In addition, the processor may beconfigured to alter a parameter of an instrument coupled to achemical-mechanical polishing tool in response to the flatnessmeasurement using a feedforward control technique. For example, theprocessor may be configured to alter a pressure of the polishing headcoupled to the chemical-mechanical polishing tool in response to theflatness measurement using a feedforward control technique. In addition,the polishing head may be configured such that pressure across thepolishing head may vary from zone to zone. Therefore, altering apressure of the polishing head may include altering a pressure of one ormore zones of the polishing head. In this manner, a system as describedherein may be used to increase a planarity of an upper surface of thespecimen subsequent to chemical-mechanical polishing.

Alternatively, such a system may be coupled to a thermal tool such as afurnace or a rapid thermal annealing furnace. As such, the flatnessmeasurement of a specimen may include a measure of stress-inducedcurvature of a specimen due to thermal processing. In addition, such asystem may also be coupled to an etch tool, a lithography tool, or awafer manufacturing tool as described herein.

In an embodiment, a system may be configured to determine at least anoverlay misregistration of a specimen and a flatness measurement of thespecimen. The system may be configured as described herein. For example,the system may include a processor coupled to a measurement device. Theprocessor may be configured to determine at least an overlaymisregistration of a specimen and a flatness measurement of the specimenfrom one or more output signals generated by the measurement device. Inaddition, the processor may be configured to determine other propertiesof the specimen from the one or more output signals. In an embodiment,the measurement device may include a non-imaging scatterometer, ascatterometer, a spectroscopic scatterometer, a reflectometer, aspectroscopic reflectometer, a spectroscopic ellipsometer, a brightfield imaging device, a dark field imaging device, a bright field anddark field imaging device, a coherence probe microscope, an interferencemicroscope, an interferometer, an optical profilometer, a dual beamspectrophotometer, a beam profile ellipsometer, or any combinationthereof. The system may be further configured to determine at least anoverlay misregistration of a specimen and a flatness measurement of thespecimen sequentially or substantially simultaneously. For example, thesystem may be coupled to a lithography tool as described herein. Inaddition, the system may be configured to determine at least a flatnessmeasurement of the specimen prior to an exposure step of a lithographyprocess. The system may also be configured to determine an overlaymisregistration of a specimen prior to the exposure step.

As described herein, a system may be configured to determine at least acharacteristic of an implanted region of the specimen and a presence ofdefects on the specimen. The system may be configured as describedherein. For example, the system may include a processor configured todetermine at least a characteristic of an implanted region of thespecimen and a presence of defects on the specimen from one or moreoutput signals generated by a measurement device. In addition, theprocessor may be configured to determine other properties of thespecimen from the one or more output signals. In an embodiment, themeasurement device may include a modulated optical reflectometer, anX-ray reflectance device, an eddy current device, a photo-acousticdevice, a spectroscopic ellipsometer, a non-imaging scatterometer, ascatterometer, a spectroscopic scatterometer, a reflectometer, aspectroscopic reflectometer, an ellipsometer, a bright field non-imagingdevice, a dark field non-imaging device, a bright field and dark fieldnon-imaging device, a bright field imaging device, a dark field imagingdevice, a bright field and dark field imaging device, a coherence probemicroscope, an interference microscope, an optical profilometer, a dualbeam spectrophotometer, or any combination thereof.

An ion implantation process typically involves producing a beam of ionsand driving at least some of the ions into a semiconductor substrate.The implantation of ions into a semiconductor substrate may alterelectrical properties of the semiconductor substrate. The electricalproperties of the implanted semiconductor substrate may vary dependingon a concentration of ions implanted into the semiconductor substrate.The electrical properties of the implanted semiconductor substrate mayalso vary depending on the depth of the implanted portion of thesemiconductor substrate and the distribution of the implanted ions as afunction of thickness. Such characteristics of the implanted region ofthe semiconductor substrate may vary depending on a number of factorsincluding, but not limited to, a type of the ions, implantation energy,implantation dose, and masking materials formed on the semiconductorsubstrate.

In some embodiments, an optical property of an upper, middle, or lowerportion of the masking material may be used to determine acharacteristic of implanted ions in the masking material such as depthof the implanted ions or a characteristic of the implantation processsuch as implantation energy. For example, during an ion implantationprocess, ions will be driven into the masking material. The implantationof ions into the masking material may cause physical damage to an uppersurface of the masking material, and ions driven into the maskingmaterial may reside in the middle portion of the masking material. Thedepth to which implantation of ions causes damage to the upper portionof the masking material may be a function of the energy of the ions. Thedepth to which the ions are driven into the masking material may also bea function of the energy of the ions. For example, higher energyimplantation processes may cause more damage to an upper portion of themasking material and may drive the ions farther into the maskingmaterial than lower energy ion implantation process. Therefore, thedepth of the upper and middle portions of the masking material may berelated to the implant energy of the ion implantation process. The depthof the upper and middle portions of the masking material may also berelated to other process conditions of the ion implantation such as thespecies of ions being implanted or the implant dose. In addition, themeasured thickness of the lower portion of the masking material may alsovary depending upon ion implantation energy. The thickness of the upper,middle, and lower portions may be determined by measuring an opticalproperty of the masking material. The implantation of ions into themasking material or the implanted masking material resulting from theion implantation process may, therefore, be determined as a function ofthe measured optical property of the masking material.

In additional embodiments, an implanted masking material may be analyzedas a single, substantially homogenous, layer. Therefore, an opticalproperty of substantially an entire implanted masking material may alsobe measured. The entire implanted masking material may include theupper, middle, and lower portions of the implanted masking material asdescribed above. The individual optical properties of the upper, middle,and lower portions may, therefore, be effectively included in themeasurement of the optical property of the entire implanted maskingmaterial. For example, an optical property of the entire implantedmasking layer may include added or averaged optical properties ofindividual layers. An optical property of a masking material measured asa single layer may be used to determine the ion implantation conditions.In one example, an optical property of substantially the entirethickness of the masking material may be compared to an optical propertyof substantially the entire thickness of the masking material prior toion implantation. Therefore, the comparison of the optical propertiesmay indicate a change in the optical property of the masking materialsubsequent to the ion implantation. A change in the optical property ofthe masking material may be attributed to implanted ions present in themasking material subsequent to an implantation process. In addition, anoptical property of substantially the entire implanted masking materialmay also be compared to an optical property of substantially an entiremasking material implanted using known conditions. In this manner,comparing the optical properties of the two implanted masking materialsmay indicate if the ion implantation process is drifting over time oracross several semiconductor substrates.

In one embodiment, the optical property of the masking material may be athickness, an index of refraction (or refractive index), or anextinction coefficient of the masking material or a portion of themasking material. The optical property of the masking material may bemeasured using a broadband radiation technique such as spectroscopicellipsometry or spectroscopic reflectometry. The thickness of themasking material may also be measured separately using an additionaloptical technique such as dual-beam spectrophotometry. Examples ofdual-beam spectrophotometry methods and systems are illustrated in U.S.Pat. No. 5,652,654 to Asimopoulos, U.S. Pat. No. 5,699,156 to Carver,and U.S. Pat. No. 5,959,812 to Carver, and are incorporated by referenceas if fully set forth herein. Additionally, several optical propertiesof the masking material may be measured simultaneously. For example, athickness of the upper, middle, and lower portions of the implantedmasking material may be measured simultaneously. In addition, an indexof refraction and an extinction coefficient may be measuredsimultaneously for an implanted masking material or a portion of animplanted masking material. Depending on the number of opticalproperties measured, several characteristics of the ion implantationprocess and/or the implanted masking material may also be determinedsimultaneously. Characteristics of the ion implantation process mayinclude, but are not limited to, implant dose, implant energy, andimplant species. Characteristics of the implanted masking material mayinclude, but are not limited to, concentration of the implanted ions inthe masking material and the presence of implanted ions in the maskingmaterial.

In an embodiment, the measured optical property of the implanted maskingmaterial may also be used to determine a characteristic of an implantedportion of the semiconductor substrate. The implanted portion of thesemiconductor substrate may be formed during the implantation of ionsinto the masking material or during subsequent ion implantationprocesses. Characteristics of an implanted portion of a semiconductorsubstrate may include a depth of the implanted portion, a concentrationof ions in the implanted portion, and a distribution of implanted ionsas a function of the thickness of the implanted portion. Suchcharacteristics may be a function of a measured optical property of themasking material. The function may describe a relationship between theoptical property of the implanted masking material and the implantationof ions into the semiconductor substrate. The function may be determinedexperimentally by implanting a masking material and a portion of asemiconductor substrate simultaneously. The optical property of theimplanted masking layer and the electrical properties of the implantedportion of the semiconductor substrate may then be measured. Theelectrical properties of the implanted portion of the semiconductorsubstrate may be related to characteristics of the implantation of ionsinto the semiconductor substrate such as depth of the implanted portionor distribution of the implanted ions as a function of thickness of thesemiconductor substrate. A number of wafers may be processed andmeasured in this manner in order to generate a set of data that may beused to determine a functional relationship between an optical propertyof an implanted masking material and a characteristic of implanted ionsin a semiconductor substrate.

Alternatively, the functional relationship may include a mathematical ortheoretical model that describes a relationship between implantation ina masking material and implantation into a semiconductor substrate. Forexample, a mathematical or theoretical model may be used to determinethe depth of an implanted portion of a semiconductor substrate usingimplant energy, implant dose, or depth of the implanted region of themasking material as determined from an optical property of the implantedmasking material. An example of a method for using spectroscopicellipsometry and spectroscopic reflectometry to monitor ion implantationis illustrated in U.S. patent application Ser. No. 09/570,135, “Methodof Monitoring Ion Implants by Examination of an Overlying MaskingMaterial” to Strocchia-Rivera, filed on May 12, 2000, issued as U.S.Pat. No. 6,462,817 on Oct. 8, 2002, and is incorporated by reference asif fully set forth herein.

Optical evaluation of an ion implantation process may provide severaladvantages over current methods to evaluate an ion implantation process.For example, an optical method may provide non-destructive testing andmay not interfere with processing of a semiconductor substrate or theperformance of a fabricated semiconductor device. Furthermore, opticalevaluation of the masking material may not require additional processingsuch as annealing of the semiconductor substrate on which the maskingmaterial is formed. Therefore, evaluation of an ion implantation processusing an optical method such as a broadband radiation technique may beperformed during the ion implantation process.

In an embodiment, a system configured to evaluate an ion implantationprocess as described herein may be coupled to an ion implanter. Thesystem may include a measurement device as described herein. Themeasurement device may be coupled to a process chamber of the ionimplanter as shown, for example, in FIG. 17. The measurement device maybe coupled to the ion implanter such that the measurement device may beexternal to the ion implanter. In this manner, exposure of thecomponents of the measurement device to chemical and physical conditionswithin the ion implanter may be reduced, and even eliminated.Furthermore, the device may be externally coupled to the ion implantersuch that the measurement device does not interfere with the operation,performance, or control of the ion implantation process.

The measurement device, however, may be configured to focus an incidentbeam of broadband radiation onto a specimen in the ion implanter. Themeasurement device may also be configured to detect at least a portionof a beam of broadband radiation returned from the specimen. Forexample, a process chamber of an ion implanter may include smallsections of a substantially optically transparent material disposedwithin walls of the process chamber. The small sections of transparentmaterial may be configured to transmit the incident and returned beamsof broadband radiation from an illumination system outside the processchamber to a specimen within the process chamber and from the specimento a detection system outside the process chamber. The opticallytransparent material may be further configured to transmit incident andreturned beams of light without undesirably altering the opticalproperties of the incident and reflected beams. An appropriate methodfor coupling a measurement device to an ion implanter may vary, however,depending upon, for example, a configuration of the ion implanter. Forexample, placement and dimensions of the transparent material sectionsdisposed within the walls of the process chamber may depend on theconfiguration of the components within the process chamber. Therefore, ameasurement device coupled to an ion implanter may be configured tomeasure optical properties of the masking material, optical propertiesof a portion of the masking material, optical properties of amulti-layer masking stack, or optical properties of the specimen duringthe implantation process.

In an additional embodiment, the system may also include a processorcoupled to the measurement device and the ion implanter. The processormay be configured to interface with the measurement device and the ionimplanter. For example, the processor may receive signals and/or datafrom the ion implanter representative of parameters of an instrumentcoupled to the ion implanter. The processor may also be configured toreceive signals and/or data from the measurement device representativeof light returned from the specimen or at least one property of theimplanted region of a specimen. Additionally, the processor may befurther configured to control the measurement device and the ionimplanter. For example, the processor may alter a characteristic of theimplanted region of the specimen by altering a parameter of aninstrument coupled to the ion implanter. Therefore, the system maymonitor and control the implantation of ions during a process.

In an additional embodiment, the system may be configured to monitor ormeasure variations in at least one optical property of the implantedmasking material. For example, the measurement device may be configuredto measure an optical property of the implanted masking materialsubstantially continuously or at predetermined time intervals during anion implantation process. The processor may, therefore, receive one ormore output signals from the measurement device that may berepresentative of light returned from the specimen. The processor mayalso monitor variations in the one or more output signals over theduration of the ion implantation process. By analyzing variations in theone or more output signals during implantation, the processor may alsogenerate a signature representative of the implantation of the ions intothe masking material. The signature may include at least one singularitythat may be characteristic of an endpoint of the ion implantationprocess. An appropriate endpoint for an ion implantation process may bea predetermined concentration of ions in a masking material or in aspecimen. In addition, the predetermined concentration of ions may varydepending upon the semiconductor device feature being fabricated by theion implantation process. After the processor has detected thesingularity of the signature, the processor may stop the implantation ofions by altering a level of a parameter of an instrument coupled to theion implanter.

In an embodiment, a method for fabricating a semiconductor device mayinclude implanting ions into a masking material and a semiconductorsubstrate. The masking material may be arranged on the semiconductorsubstrate such that predetermined regions of the semiconductor substratemay be implanted with ions. For example, portions of the maskingmaterial may be removed by a lithography process and/or etch process toexpose regions of the semiconductor substrate to an implantationprocess. During an ion implantation process, typically, an entiresemiconductor substrate may be scanned with a beam of dopant ions.Therefore, the remaining portions of masking material may inhibit thepassage of dopant ions into underlying regions of the semiconductorsubstrate during an ion implantation process. As such, patterning themasking material may provide selective implantation of ions into exposedregions of the specimen.

The exposed regions may be regions of a specimen in which features of asemiconductor device are to be formed. For example, a dielectricmaterial overlying a channel region of a gate during an ion implantationprocess may prevent implantation of ions into the gate conductor or thechannel region beneath the gate conductor. The exposed regions of thespecimen may, therefore, correspond to a particular feature of thesemiconductor device being fabricated such as a junction region.Alternatively, ions may be implanted through a masking material and intounderlying regions of the semiconductor substrate. In this manner, themasking material may include a thin gate dielectric material arrangedover junction regions of a transistor. Implantation of ions through amasking material may enhance the electrical properties of the implantedregion of the semiconductor substrate, for example, by randomizing thedirectional paths of the ions which are being driven into the specimen.The masking material may also be formed over a substantially planarspecimen or over a non-planar specimen.

Fabricating a semiconductor device may also include monitoringimplantation of ions into the semiconductor substrate by measuring atleast one optical property of the masking material during the ionimplantation process. The optical property of the masking material maybe altered by the implantation of ions into the masking material. Assuch, the method for fabricating a semiconductor device may also includedetermining at least one characteristic of the implanted ions in thesemiconductor substrate. The characteristic may be determined, forexample, using a function that describes a relationship between theoptical property of the implanted masking material and the implantationof ions into the semiconductor substrate.

In an embodiment, any material that may be substantially transparent toat least a portion of the light produced by a measurement device, asdescribed above, may be used as a masking material for evaluation of anion implantation process involving measurement of optical properties ofa masking material. In one embodiment, the masking material may be aresist. An appropriate resist may include photoresist materials that maybe patterned by an optical lithography technique. Other resists,however, may also be used such as e-beam resists or X-ray resists, whichmay be patterned by an e-beam or an X-ray lithography technique,respectively. In another embodiment, the masking material may include aninorganic material. Inorganic masking materials that may be used toinhibit ion implantation include, but are not limited to, silicondioxide, silicon nitride, titanium nitride, polycrystalline silicon,cobalt silicide, and titanium silicide. The inorganic masking materialmay be formed by deposition techniques, such as chemical vapordeposition, or thermal growth techniques. The inorganic maskingmaterials may be patterned using an etch technique.

In another embodiment, the masking material may include two or morelayers of different masking materials arranged in a stack. For example,the masking material may include a resist formed upon an inorganicmaterial. The inorganic material may include any material that inhibitsthe implantation of ions through the masking material. When used as partof a masking material, the inorganic material may not be transparent ormay not exhibit any substantial changes in optical properties whenexposed to ions. The subsequent optical analysis may be done on theoverlying resist material rather than on the underlying inorganicmasking material. The inorganic material may be formed on a specimenprior to coating the specimen with a resist. This additional inorganicmaterial, in combination with an overlying resist, may serve as themasking stack. An appropriate masking material may vary depending on,for example, an ion implantation process or an ion implanterconfiguration.

During ion implantation processes, and especially in processes usingrelatively high dosage levels, a semiconductor substrate may besignificantly damaged due to the implantation of dopant ions intoregions of the semiconductor substrate. For example, an implanted regionof such a damaged semiconductor substrate may include of an uppercrystalline damaged layer and an intermediate layer of amorphoussilicon. The damage in the upper crystalline layer may be caused, forexample, by electronic collisions between atoms of the semiconductorsubstrate and the implanted ions. Displacement damage, however, may notbe produced if ions entering the semiconductor substrate do not haveenough energy per nuclear collision to displace silicon atoms from theirlattice sites. Increasing the dose of ions, and in particular relativelyheavy ions, may produce an amorphous region in which the displaced atomsper unit volume may approach the atomic density of the semiconductorsubstrate. As the implant dose of the ion implantation processincreases, the thickness of the amorphous layer may also increase. Thepresence of an amorphous layer of silicon may act as a boundary that mayreflect optical radiation. Reflection of light by the amorphous layermay also effect the reflectance and ellipsometric measurements.Therefore, measurement of an optical property of the amorphous siliconlayer may also be used to monitor the processing conditions of an ionimplantation process.

In an embodiment, an optical property of an implanted portion of asemiconductor substrate may be measured. The optical property may be athickness, an index of refraction, or an extinction coefficient of theimplanted portion. In addition, several optical properties of theimplanted portion of the semiconductor substrate may be measuredsubstantially simultaneously. The optical property of the implantedportion of the semiconductor substrate and the optical property of theimplanted masking material may also be measured substantiallysimultaneously. A characteristic of the implanted ions in thesemiconductor substrate may be determined from the measured opticalproperty of the implanted portion of the semiconductor substrate. Thischaracteristic may, therefore, be related to the implantation of ionsinto a portion of the semiconductor substrate or a characteristic of theresulting implanted semiconductor substrate. For example, thecharacteristic may be an implant energy, an implant dose, or an implantspecies of the ion implantation process. In addition, the characteristicmay be a concentration of ions, a depth, a distribution of the implantedions as a function of thickness, or a presence of the implanted ions inthe implanted portion of the semiconductor substrate. In addition,optical properties of the implanted portion of the semiconductorsubstrate may be used to determine several characteristics substantiallysimultaneously, which may include, but are not limited to, any of thecharacteristics as described above. A characteristic of thesemiconductor substrate and a characteristic of the implanted ions inthe masking material may also be determined substantiallysimultaneously.

In an additional embodiment, optical properties of the implanted portionof the semiconductor substrate may be measured using a broadbandwavelength technique as described herein. For example, a measurementdevice, as described herein, may be configured to use a broadbandwavelength technique to measure optical properties of an implantedportion of a semiconductor substrate. Additionally, the measurementdevice may be coupled to an ion implanter as described above such thatmeasuring an optical property of the implanted portion of thesemiconductor substrate may be performed during an ion implantationprocess. Therefore, variations in an optical property of the implantedportion of the semiconductor substrate may also be measured during anion implantation process. In this manner, a signature characterizing theimplantation of ions into the semiconductor substrate may be obtained.This signature may include a singularity characteristic of an end of theimplantation process. As described above, an appropriate endpoint maybe, for example, a predetermined concentration of ions in thesemiconductor substrate. An appropriate processor, as described herein,may then reduce or substantially stop processing of the semiconductorsubstrate by controlling the ion implanter.

In an embodiment, the measured optical properties of the implantedmasking material may be used to determine processing conditions forsubsequent ion implantation processes of additional specimens such asadditional semiconductor substrates or semiconductor device productwafers. For example, the implant energy of the implantation of ions intothe masking material may be determined using the measured opticalproperty of the implanted masking material. The determined implantenergy may be used to determine depth of an implanted portion of asemiconductor substrate during an ion implantation process. The depth ofthe implanted portion of the semiconductor substrate may also bedetermined from a measured optical property of the implanted portion ofthe semiconductor substrate.

The determined depth of the implanted portion of the semiconductorsubstrate may be less than a predetermined depth. The predetermineddepth may vary depending on, for example, a feature fabricated duringthe ion implantation process. Therefore, before processing additionalsemiconductor substrates, or product wafers, the implant energy oranother process condition of the ion implantation process may be alteredsuch that a depth of an implanted portion of the additionalsemiconductor substrates may be approximately equal to the predetermineddepth. For example, an implant energy of the ion implantation processmay be increased to drive the ions deeper into the semiconductorsubstrate. In this manner, measured optical properties of a maskingmaterial may be used to determine and alter process conditions of an ionimplantation process using a feedback control technique. In anadditional embodiment, measured optical properties of an implantedportion of a semiconductor substrate may be used to determine and alterprocess conditions of an ion implantation process using a feedbackcontrol technique.

In an additional embodiment, measured optical properties of an implantedmasking material may be used to determine process conditions ofadditional semiconductor fabrication processes that may be performedsubsequent to an ion implantation process. Additional semiconductorfabrication processes may include, but are not limited to, a process toanneal the implanted regions of a semiconductor substrate and a processto remove the masking material. For example, an implant energy of an ionimplantation process may be determined using a measured optical propertyof an implanted masking material. The determined implant energy may beused to determine a depth that ions may be implanted into asemiconductor substrate using the ion implantation process.Alternatively, a depth of the implanted portion of a semiconductorsubstrate may also be determined using a measured optical property ofthe implanted semiconductor substrate.

The determined depth of the implanted portion of the semiconductorsubstrate may be greater than a predetermined depth. Process conditionsof an annealing process performed subsequent to the ion implantationprocess, however, may be optimized for the predetermined depth.Therefore, before annealing an implanted semiconductor substrates havingthe determined depth, a process condition of the annealing process suchas anneal time or anneal temperature may be altered. In this example,the anneal time of the annealing process may be increased to ensuresubstantially complete recrystallization of the amorphous layer formedin the semiconductor substrate by the ion implantation process. In thismanner, measured optical properties of a masking material may be used todetermine process conditions of a semiconductor fabrication processperformed subsequent to an ion implantation process using a feedforwardcontrol technique. Measured optical properties of an implanted portionof a semiconductor substrate may also be used to determine processconditions of a semiconductor fabrication process performed subsequentto an ion implantation process using a feedforward control technique.

A set of data that may include measured optical properties of a maskingmaterial may be collected and analyzed. The set of data may be used todetermine processing conditions of an ion implantation process or tomonitor the processing conditions over time. Process control methods asdescribed herein may also be used in conjunction with electrical testingof an implanted region of a semiconductor substrate. The combination ofoptical and electrical analysis may provide a larger amount ofcharacterization data for an ion implantation process. Thecharacterization data may be used to assess the mechanisms of ionimplantation, to determine the cause of defects, and to alter processconditions. In addition, this process control strategy may be used toqualify, or characterize the performance of, a new ion implanter.Furthermore, this process control strategy may be used to determine anappropriate masking material and masking material thickness indevelopment of an ion implantation process. The process control methodmay also be used to compare the performance of two or more ionimplanters. Such a process control method may be used in a manufacturingfacility in which several ion implanters may be used in parallel tomanufacture one type of device or product.

In an embodiment, a system may be configured to determine at least anadhesion characteristic of a specimen and a thickness of the specimen.The system may be configured as described herein. For example, thesystem may also include a processor coupled to a measurement device. Inaddition, the processor may be configured to determine other propertiesof the specimen from the detected light. In an embodiment, themeasurement device may include a photo-acoustic device, a spectroscopicellipsometer, an ellipsometer, an X-ray reflectometer, a grazing X-rayreflectometer, an X-ray diffractometer, a non-imaging scatterometer, ascatterometer, a spectroscopic scatterometer, a reflectometer, aspectroscopic reflectometer, a bright field imaging device, a dark fieldimaging device, a bright field and dark field imaging device, acoherence probe microscope, an interference microscope, an opticalprofilometer, an eddy current device, an acoustic pulse device, or anycombination thereof. The processor may be configured to determine atleast an adhesion characteristic and a thickness of the specimen fromone or more output signals from the measurement device.

In an embodiment, an acoustic pulse device or a photo-acoustic devicemay be configured to use acoustic pulses to characterize a layer formedupon a specimen. For example, acoustic pulses may be used to determine athickness of a layer such as a metal disposed on a specimen. Anadvantage of an acoustic pulse device is that measuring a property of alayer formed on a specimen with the device is substantiallynon-destructive. An acoustic pulse device may be configured to apply alaser pulse to a specimen. The laser pulse may be absorbed within oneabsorption length from an upper surface of the layer thereby causing arise in local surface temperature. Depending on temperature coefficientof expansion (expansivity) of a layer, the layer may undergo thermalstresses, which may generate an elastic pulse in the layer. The elasticpulse may propagate across the layer at approximately the velocity ofsound. The time of flight for the elastic pulse across the layer may bemeasured and may be used to determine a thickness of the layer.Measuring the time of flight for the elastic pulse may include steps ofthe methods described below.

In one embodiment, a laser pulse of radiation may be applied to a firstsurface area of a specimen to non-destructively generate an elasticpulse in the specimen. The elastic pulse may cause the first surfacearea to move. The acoustic pulse device may include an interferometerconfigured to detect an acoustic echo of the pulse traversing thespecimen. The interferometer may also be configured to provide a pair ofpulses including a probe pulse and a reference pulse of radiation. Theinterferometer may be further configured to direct the probe pulse tothe first surface area when it is moved by the elastic pulse and areference pulse to a second surface area. The second surface area may belaterally spaced from the first surface area. The interferometer mayalso be configured to monitor the reflection of the pulses off of thesurface of the specimen. The reflection of the pair of pulses may beused to determine a thickness of a layer on the specimen. For example, aprocessor of the system may be configured to determine a thickness ofthe layer using one or more output signals from the interferometer.

In an embodiment, a method for non-destructively measuring properties ofa specimen may include directing a pump pulse of radiation to a firstsurface area of the specimen to non-destructively generate an elasticpulse in the specimen. The generated elastic pulse may cause the firstsurface area to move. The method may also include directing a probepulse and a reference pulse of radiation to the specimen using aninterferometer. Directing the probe and reference pulses may includedirecting the probe pulse to the first surface area when it is moved bythe elastic pulse and directing the reference pulse to a second surfacearea. The second surface area may be laterally spaced from the firstsurface area. In addition, the method may include monitoring reflectionsof the probe and reference pulses. The method may also includedetermining a thickness of a layer on the specimen. Both of the abovedescribed acoustic-pulse methods are described in further detail in U.S.Pat. No. 6,108,087 to Nikoonahad et al. and U.S. patent application Ser.No. 09/310,017, issued as U.S. Pat. No. 6,268,916 on Jul. 31, 2001 toLee et al., both of which are incorporated by reference as if fully setforth herein. Other methods for measuring films using acoustic waves arealso described in U.S. Pat. No. 6,108,087.

In another embodiment, an acoustic pulse device may be configured todetermine a thickness of a layer by using a probe pulse and a referencepulse that are substantially in phase with each other. The in-phasepulses may be used to measure an acoustic echo created by a pump pulseapplied to an area of the layer. The applied pump pulse may create anelastic pulse that may propagate through the layer. The probe pulse maybe directed to the area of the specimen through which the elastic pulsepropagates. The reference pulse may be directed to substantially thesame surface area or a different surface area of the sample such thatthe pair of pulses may be modified by the specimen. The modified pulsesmay interfere at a detector. For example, at least one of the pulses maybe modulated in phase or frequency before or after modification by thesample and prior to detection by the detector. By processing one or moreoutput signals from the detector, a thickness of a layer on the specimenmay be determined.

In one embodiment, an optical delay may be used to alter a timerelationship between the pump pulse and the probe pulse. In this manner,the probe pulse may be directed to the specimen surface when it isinfluenced by the elastic pulse created by the pump pulse. The referenceand probe pulses may be directed along substantially the same opticalpath between an optical source and a detector. Such a configuration mayreduce, and even minimize, random noise in one or more output signals ofthe detector, which may be caused, for example, by environmentalfactors. Such a configuration is further described in U.S. patentapplication Ser. No. 09/375,664, issued as U.S. Pat. No. 6,552,803 onApr. 22, 2003 to Wang et al., which is incorporated by reference as iffully set forth herein.

Acoustic pulse devices, as described above, may be incorporated into anyof the systems and/or process tools as described herein.

In an embodiment, a system may be configured to determine at least aconcentration of an element in a specimen and a thickness of a layer onthe specimen. The system may be configured as described herein. Forexample, the system may also include a processor coupled to ameasurement device. The processor may be configured to determine atleast a concentration of an element in a specimen and a thickness of alayer formed on the specimen from one or more output signals generatedby the measurement device. In addition, the processor may be configuredto determine other properties of the specimen from the detected light.In an embodiment, the measurement device may include a photo-acousticdevice, an X-ray reflectometer, a grazing X-ray reflectometer, an X-raydiffractometer, an eddy current device, a spectroscopic ellipsometer, anellipsometer, a non-imaging scatterometer, a scatterometer, aspectroscopic scatterometer, a reflectometer, a spectroscopicreflectometer, a bright field imaging device, a dark field imagingdevice, a bright field and dark field imaging device, a coherence probemicroscope, an interference microscope, an optical profilometer, an eddycurrent device, or any combination thereof.

An X-ray reflectance (“XRR”) technique may be used to measure a propertyof a specimen such as a concentration of an element in a thickness of alayer or at an interface between layers on a specimen. X-ray reflectancemay also be used to determine a thickness of a layer or an interfacebetween layers on a specimen. Layers which may be measured by X-rayreflectance may include layers substantially transparent to light suchas dielectric materials and layers substantially opaque to light such asmetals. X-ray reflectance may include irradiating a surface of aspecimen with X-rays and detecting X-rays reflected from the surface ofthe specimen. A thickness of a layer may be determined based oninterference of X-rays reflected from the surface of the specimen. Inaddition, reflection of X-rays from the surface of the specimen may varydepending on refractive index changes at a surface of a layer on thespecimen and at an interface between layers on the specimen and thedensity of the layer or of the interface. Therefore, a complexrefractive index in an X-ray regime may be directly proportional to adensity of a layer. In this manner, a concentration of an element in alayer or at an interface between layers may be determined based on thedensity and thickness of the layer.

X-ray reflectance may be performed at different angles of incidencedepending upon, for example, characteristics of a specimen. An X-rayreflectance curve may be generated by a processor using one or moreoutput signals responsive to the detected X-rays reflected from thesurface of the specimen. The X-ray reflectance curve may include anaverage reflectance component, which may be caused by bulk properties ofthe specimen. The average reflectance component may be subtracted fromthe one or more output signals such that an interference oscillationcomponent curve may be generated. Parameters of the interferenceoscillation component curve may be converted, and a Fourier transformmay be performed. A thickness of a layer may be determined by a positionof a peak of a Fourier coefficient, F(d). In addition, a peak intensityof the Fourier coefficient, F(d), may be used to determine a layerdensity or an interface density. For example, a relationship between apeak intensity of a Fourier coefficient and a layer density may besimulated and may be used to determine a layer density. Alternatively, alayer density may be determined based on the X-ray reflectance curve byfitting the curve to model data using a mathematical method such as anonlinear least squares curve-fitting method. In such a method, severalof the fitted parameters may be inter-related. Therefore, parametersthat may be substantially constant across specimens may be fixed ataverage values in order to prevent multiple solutions.

A concentration of an element on a surface of a layer or at an interfacebetween layers may be determined by using data that may describe arelationship between interface layer density and concentration. The datamay be generated by another analytical technique such as secondary ionmass spectroscopy (“SIMS”). SIMS may involve removing material from asample by sputtering ions from the surface of the sample and analyzingthe sputtered ions by mass spectrometry. Examples of SIMS techniques areillustrated in U.S. Pat. No. 4,645,929 Criegern et al., U.S. Pat. No.4,912,326 to Naito, U.S. Pat. No. 6,078,0445 to Maul et al., and U.S.Pat. No. 6,107,629 to Benninghoven et al., and are incorporated byreference as if fully set forth herein. In this manner, a plurality ofsamples having various elemental concentrations may be prepared. Thesamples may be analyzed by XRR to determine density of the layer orinterface of interest and may also be analyzed by SIMS to determine aconcentration of the layer or interface of interest. A relationshipbetween density and concentration may then be determined. The determinedrelationship may be used to determine concentration of an element on asurface of a layer or at an interface between layers in additionalspecimen.

A device configured to measure X-ray reflectance of a layer or aninterface between layers of a specimen may include a measurementchamber. A specimen may be supported within the measurement chamber by astage or another mechanical device. An appropriate stage or mechanicaldevice may be configured to maintain a position of the specimen duringmeasurement and for moving the specimen before, during, and/or afterX-ray reflectance measurements. The stage or mechanical device may alsobe further configured as described herein. The measurement chamber mayalso be configured as a process chamber of a process tool, which may beused for semiconductor fabrication. For example, the process chamber mayinclude a deposition chamber in which a metal film may be formed on aspecimen or an ion implantation chamber in which ions may be driven intoa specimen. In this manner, X-ray reflectance measurements may beperformed prior to, during, or subsequent to a process performed in theprocess chamber. The measurement chamber may also be disposed within orproximate a process tool such that a specimen may be moved from aprocess chamber of the process tool to the measurement chamber. In oneexample, the measurement chamber may be coupled to a chemical-mechanicalpolishing tool such that X-ray reflectance measurements may be performedprior to or subsequent to a process step of a chemical-mechanicalpolishing process.

The device configured to measure X-ray reflectance of a layer or aninterface between layers of a specimen may also include an X-ray sourcesuch as a rotor X-ray source. X-rays generated by the X-ray source maybe passed through a germanium monochromator. The measurement chamber mayalso include a beryllium window in a wall of the measurement chamberthrough which the X-rays may enter the measurement chamber. In thismanner, X-rays may be directed to a surface of a specimen supportedwithin the measurement chamber. In addition, the device may include anX-ray detector arranged on a side of the measurement chamber opposite tothe X-ray source. As such, X-rays reflected from the surface of thespecimen may be detected. The system may also include a controllercomputer configured to control the device and/or individual componentsof the device. The controller computer may also be configured to processa signal generated by the detector in response to the detected X-raysand to determine a concentration of an element in a layer or aninterface between layers of a specimen. The controller computer may befurther configured as a processor as described herein. Additionalexamples of X-ray reflectance methods and systems are illustrated inU.S. Pat. No. 5,740,226 to Komiya et al. and U.S. Pat. No. 6,040,198 toKomiya et al., which are incorporated by reference as if fully set forthherein.

In an embodiment, an eddy current device may be configured to measure athickness of a layer formed upon a specimen. Eddy current devices mayalso be configured to measure junction leakage in a specimen. An eddycurrent device may include a sensor configured to apply an alternatingcurrent to a specimen. The applied alternating current may cause an eddycurrent in the specimen. The resistance or conductance of the specimenmay be analyzed using the eddy current. A thickness of a layer on thespecimen may be determined by a change in resistance or conductivity.Methods for using eddy currents to determine a thickness of a layer on aspecimen are illustrated in U.S. Pat. No. 6,086,737 to Harada, and U.S.patent application Ser. No. 09/633,198 entitled “In-situ metalizationmonitoring using eddy current measurements during the process forremoving the film,” by K. Lehman, S. M. Lee, W. Johnson, and J. Fielden,issued as U.S. Pat. No. 6,433,541 on Aug. 13, 2002, which areincorporated by reference as if fully set forth herein.

A sensor or an eddy current device may include a capacitor and aninductor. During use, the sensor may be positioned proximate to thespecimen. When a layer formed on the specimen is conductive or magnetic,the inductor may be configured to couple an alternating (“ac”)electromagnetic field to the layer. The alternating electromagneticfield may induce eddy (i.e., Foucault) currents in the layer, and twoeffects may be present. First, the layer may act as a lossy resistor,and the effect will be a resistive loading on a sensor circuit, whichwill lower the amplitude of the resonant signal and lower the resonantfrequency. Second, a decrease in the layer thickness may produce aneffect as though a metal rod were being withdrawn from the coil of theinductor thereby causing a change in inductance as well as a frequencyshift. As the thickness of the layer changes, either by addition orremoval, the eddy currents may change, and thus their resistive loadingeffect and magnitude of frequency shift may change as well. When a layeris not present, there will be no effect on the sensor circuit (i.e., noresistive loading, no inductance change, no frequency shift). Thus, achange in thickness of a layer may be monitored substantiallycontinuously or intermittently by monitoring changes in any of theseparameters.

Note that any conductive film may be monitored using an eddy currentdevice, not just a layer such as a thin film on a semiconductorsubstrate. For example, in an electroplating process, metal ions in aplating solution dissolved from a metal block electrode acting as ananode may be deposited on a target at the cathode to form a film. Eddycurrent measurements may be used to monitor formation of the film on thetarget during the electroplating process, both in-situ and real time.

Eddy current devices and measurements may be used in a variety ofapplications. In one embodiment, an eddy current device may be coupledto a chemical mechanical polishing tool. In this application, the eddycurrent device may be used to determine one or more endpoints of thepolishing process and/or a thickness of one or more polished layersprior to, during, or subsequent to the polishing process. In anotherembodiment, an eddy current device may be coupled to a deposition tool.In this case, the eddy current device may be utilized to detect athickness of a deposited layer, either after the layer is deposited orwhile the layer is being deposited. The eddy current device may also beused to determine one or more endpoints of the deposition process.

In another method, monitoring eddy current characteristics and surfacephotovoltage may be used in combination to determine a junction leakagein a specimen. Generally, a specimen such as a semiconductor substratemay include a first type junction and a second type junction. Junctionleakage may be monitored by applying varying light to the semiconductorsubstrate, measuring a surface photovoltage created on the surface ofthe semiconductor substrate, and measuring the eddy currentcharacteristic for the semiconductor substrate in response to the light.A junction leakage characteristic of at least one of the junction typesmay be determined from the combination of surface photovoltage and theeddy current characteristics. The use of eddy current monitoring tomeasure junction leakage is described in further detail in U.S. Pat. No.6,072,320 to Verkuil, which is incorporated herein by reference.

Eddy current measurement devices may be included in any of the systems,as described herein. For example, a system may include an eddy currentmeasurement device coupled to a measurement device configured as aspectroscopic ellipsometer. In this manner, a processor of the systemmay be configured to determine at least two characteristics of aspecimen, which may include a thickness of a layer on a specimen and acritical dimension of a feature on the specimen. The layer may include abarrier layer, and the feature may include a “seat.”

A system including an eddy current measurement device and aspectroscopic ellipsometer may be coupled to a process tool such as anatomic layer deposition (“ALD”) tool. ALD may be used to form a barrierlayer and/or a seat. ALD may typically be a technique for depositingthin films that may involve separating individual reactants and takingadvantage of the phenomenon of surface adsorption. For example, when aspecimen is exposed to a gas, the specimen may be coated with a layer ofthe gas. Upon removing the gas, for example, by pumping the gas out ofthe process chamber with a vacuum pump, under certain circumstances amonolayer of the gas may remain on a surface of the specimen. Atrelatively moderate temperatures (i.e., room temperature), the monolayermay be held relatively weakly on the surface of the specimen by physicaladsorption forces. At higher temperatures, a surface chemical reactionmay occur, and the gas may be held relatively strongly on the surface ofthe specimen by chemisorption forces. A second reactant may beintroduced to the process chamber such that the second reactant mayreact with the adsorbed monolayer to form a layer of solid film. In thismanner, relatively thin solid films such as barrier layers may be grownone monolayer at a time. In addition, such thin solid films may beamorphous, polycrystalline, or epitaxial depending on, for example, thespecific process.

FIG. 23 illustrates an embodiment of a system configured to evaluate adeposition process. In an embodiment, a system may include measurementdevice 238 coupled to deposition tool 240. Measurement device 238 may becoupled to deposition tool 240 such that the measurement device may beexternal to a process chamber of the deposition tool. As such, exposureof the measurement device to chemical and physical conditions within theprocess chamber may be reduced, and even eliminated. Furthermore, themeasurement device may be externally coupled to the process chamber suchthat the measurement device may not alter operation, performance, orcontrol of the deposition process. For example, a process chamber mayinclude relatively small sections of a substantially opticallytransparent material 242 disposed within walls of the process chamber.The configuration of a deposition tool, however, may determine anappropriate method to couple the measurement device to the depositiontool. For example, placement and dimensions of substantially opticallytransparent material sections 242 disposed within the walls of theprocess chamber may vary depending on, for example, the arrangement ofthe components within the process chamber. In addition, measurementdevice 238 may be coupled external to the process chamber such that themeasurement device may direct energy to a surface of the specimen andmay detect energy returned from a surface of the specimen as a specimenis being placed within and/or being removed from the process chamber. Asurface of the specimen may include a front side of the specimen or aback side of the specimen.

The deposition tool may be a chemical vapor deposition tool or aphysical vapor deposition tool configured to deposit dielectricmaterials or conductive materials. Examples of deposition tools areillustrated in U.S. Pat. No. 4,232,063 to Rosier et al., U.S. Pat. No.5,695,568 to Sinha et al., U.S. Pat. No. 5,882,165 to Maydan et al.,U.S. Pat. No. 5,935,338 to Lei et al., U.S. Pat. No. 5,963,783 to Lowellet al., U.S. Pat. No. 6,103,014 to Lei et al., U.S. Pat. No. 6,112,697to Sharan et al., and U.S. Pat. No. 6,114,216 to Yieh et al., and PCTApplication Nos. WO 99/39183 to Gupta et al., WO 00/07226 to Redinbo etal., and are incorporated by reference as if fully set forth herein.

In an alternative embodiment, measurement device 238 may be disposed ina measurement chamber, as described with respect to and shown in FIG.16. The measurement chamber may be coupled to deposition tool 240, asshown in FIG. 17. For example, the measurement chamber may be disposedlaterally or vertically proximate one or more process chambers ofdeposition tool 240. For example, the deposition tool may include acluster of process chambers that may each be configured to performsubstantially similar processes or different processes. In addition, themeasurement chamber may disposed laterally or vertically proximate aload chamber of deposition tool 240. A load chamber of a deposition toolmay be configured to support multiple specimens such as a cassette ofwafers that are to be processed in the deposition tool. A robotic waferhandler may be configured to remove a specimen from the load chamberprior to processing and to dispose a processed specimen into the loadchamber. Furthermore, the measurement chamber may be disposed in otherlocations proximate a deposition tool such as anywhere proximate thedeposition tool where there is sufficient space for the system andanywhere a robotic wafer handler may fit such that a specimen may bemoved between a process chamber and the system.

In this manner, a robotic wafer handler of deposition tool 240, stage264, or another suitable mechanical device may be configured to movespecimen 246 to and from the measurement chamber and process chambers ofthe deposition tool. In addition, the robotic wafer handler, the stage,or another suitable mechanical device may be configured to move specimen246 between process chambers of the deposition tool and the measurementchamber. Measurement device 238 may be further coupled to depositiontool 240 as further described with respect to FIG. 17.

Measurement device 238 may include first illumination system 244configured to direct light having a known polarization state to specimen246 such that a region of the specimen may be illuminated prior to,during, or subsequent to a deposition process. A portion 249 of thelight directed to specimen 246 by first illumination system 244 maypropagate from the illuminated region of the specimen. In addition, themeasurement device may include detection system 248 configured toanalyze a polarization state of light 249 propagating from the surfaceof specimen 246 prior to, during, or subsequent to a deposition process.In this manner, the measurement device may be configured to operate as aspectroscopic ellipsometer.

In addition, measurement device 238 may include second illuminationsystem 250 configured to direct light having a known polarization stateto specimen 246 such that a region of the specimen may be illuminatedduring a deposition process. A portion 251 of the light directed tospecimen 246 by second illumination system 250 may propagate from theilluminated region of the specimen along a path of the directed light.In addition, the measurement device may include detection system 252configured to measure an intensity of the light propagating from thesurface of specimen 246 prior to, during, or subsequent to a depositionprocess. In this manner, the measurement device may also be configuredto operate as a spectroscopic reflectometer. The measurement device,however, may also be configured to operate as a beam profileellipsometer and a null ellipsometer.

The relatively small sections of substantially optically transparentmaterial 242 may be configured to transmit light from light source 254of first illumination system 244 outside the process chamber to asurface of specimen 246 within the process chamber and to transmit lightpropagating from the surface of the specimen to detector 256 outside theprocess chamber. In addition, relatively small sections of substantiallyoptically transparent material 242 may be configured to transmit lightfrom light source 258 of second illumination system 250 outside theprocess chamber to a surface of specimen 246 within the process chamberand to transmit light propagating from the surface of the specimen todetectors 260 and 262 outside the process chamber. The substantiallyoptically transparent material may have optical or material propertiessuch that the light from light sources 254 and 258 and the lightpropagating from a surface of specimen 246 may pass through relativelysmall sections 242 disposed within process chamber without undesirablyaltering the optical properties of the directed and returned light. Inaddition, the substantially optically transparent material may beconfigured to focus light from light sources 254 and 258 onto thesurface of specimen 246. In this manner, measurement device 238 may becoupled to stage 264 disposed within the process chamber. Stage 264 maybe configured as described herein.

Spectroscopic ellipsometry may include focusing an incidence beam ofpolarized light on a specimen and monitoring a change in polarizationfor at least a portion of the incidence beam reflected from the specimenacross a broad spectrum of wavelengths. Examples of spectroscopicellipsometers are illustrated in U.S. Pat. No. 5,042,951 to Gold et al.,U.S. Pat. No. 5,412,473 to Rosencwaig et al., U.S. Pat. No. 5,581,350 toChen et al., U.S. Pat. No. 5,596,406 to Rosencwaig et al., U.S. Pat. No.5,596,411 to Fanton et al., U.S. Pat. No. 5,771,094 to Carter et al.,U.S. Pat. No. 5,798,837 to Aspnes et al., U.S. Pat. No. 5,877,859 toAspnes et al., U.S. Pat. No. 5,889,593 to Bareket et al., U.S. Pat. No.5,900,939 to Aspnes et al., U.S. Pat. No. 5,910,842 to Piwonka-Corle etal., U.S. Pat. No. 5,917,594 to Norton, U.S. Pat. No. 5,973,787 toAspnes et al., and U.S. Pat. No. 6,256,097 to Wagner and areincorporated by reference as if fully set forth herein. Additionalexamples of spectroscopic devices are illustrated in PCT Application No.WO 99/02970 to Rosencwaig et al. and is incorporated by reference as iffully set forth herein.

Light source 254 may include any of the light sources as describedherein, which may be configured to emit broadband light. Illuminationsystem 244 may include optical component 266 positioned along a path ofthe emitted light. Optical component 266 may be configured to alter apolarization state of the emitted light such that light having a knownpolarization state such as linearly or circularly polarized light may bedirected to a surface of specimen 246. In addition, illumination system244 may also include an additional optical component (not shown)configured to focus and direct light emitted from light source 254 tothe surface of specimen 246. Detection system 248 may also includeoptical component 268 positioned along a path of the light propagatingfrom the surface of the specimen. Optical component 268 may beconfigured to function as an analyzer of a spectroscopic ellipsometer.Detection system 248 may also include a dispersion element such as aspectrometer (not shown). The dispersion element may be configured toseparate light propagating from the surface of the specimen havingdifferent wavelengths. The separated components of the beam may bedetected by individual elements of detector 256, which may be configuredto function as a detector array. The polarizer may be configured torotate such that a time varying intensity may be detected by theelements of the detector array. Processor 270 may be configured toreceive one or more output signals from detector 256 and may beconfigured to process the data.

Output signals from detector 256 may be responsive to an intensity oflight at elements of the detector array. Processor 270 may be configuredto convert the output signals to ellipsometric parameters, ψ and δ, bymathematical equations known in the art as described above. Processor270 may be configured to convert the ellipsometric parameters, ψ and δ,to a property of a layer being formed upon a surface of specimen 246using a mathematical, or optical, model as described herein. Forexample, processor 270 may be configured to determine a thickness, anindex of refraction, and an extinction coefficient of a layer, a portionof a layer, or several layers on specimen 246 from the ellipsometricparameters by using an optical model. A thickness, an index ofrefraction, and an extinction coefficient may be commonly referred to as“thin film” characteristics of a layer.

Alternatively, processor 270 may be configured to determine a criticaldimension of a feature on specimen 246 from one or more output signalsfrom measurement device 238. For example, a critical dimension of afeature may include, but is not limited to, a lateral dimension such asa width, a vertical dimension such as a height, and a sidewall profileas described herein. In addition, processor 270 may be furtherconfigured to determine a thickness, an index or refraction, and/or anextinction coefficient of a layer of the specimen, and a criticaldimension of a feature on the specimen from one or more output signalsfrom measurement device 238. For example, processor 270 may beconfigured to compare one or more output signals from the measurementdevice with one or more predetermined tables that may include expectedoutput signals versus wavelength for different characteristics such aswidth, height, and sidewall profile. Expected output signals versuswavelength for different characteristics of a predetermined table may bedetermined, for example, experimentally with specimens of knowncharacteristics and/or theoretically through mathematical modeling.

In addition, processor 270 may be configured to compare one or moreoutput signals from measurement device 238 with one or morepredetermined tables that may include expected output signals versuswavelength for different characteristics and interpolated data betweenthe expected output signals versus wavelength. Alternatively, processor270 may be configured to perform an iteration using one or more startingguesses through (possibly approximate) equations to converge to a goodfit for one or more output signals from the measurement device. Suitableequations may include, but are not limited to, any non-linear regressionalgorithm known in the art.

In an additional embodiment, the system may further include acalibration ellipsometer (not shown). The calibration ellipsometer maybe configured to determine a thickness of a reference layer on aspecimen. The thickness of the reference layer may then be measuredusing the spectroscopic ellipsometer of the measurement device asdescribed herein. A phase offset of the thickness measurements of thereference layer generated by the calibration ellipsometer and themeasurement device may be determined by processor 270. The processor maybe configured to use the phase offset to determine additional layerthicknesses from measurements made by the measurement device. Thecalibration ellipsometer may also be coupled to the process chamber ofthe deposition tool. As such, the calibration ellipsometer may be usedto reduce, and even eliminate, variations in measured ellipsometerparameters. For example, measurements of the ellipsometric parameter, δ,may vary due to changing environmental conditions along one or moreoptical paths of the measurement device. Such a variation in theellipsometric parameter, δ, may alter thickness measurements of a layeron a specimen. Therefore, a calibration ellipsometer may be used toreduce, and even eliminate, a drift in thickness measurements of a layeron a specimen.

Spectroscopic reflectometry may include focusing a broadband radiationbeam on a specimen and measuring a reflectance spectrum and index ofrefraction of the specimen from which a thickness of a layer may bedetermined. Example of spectroscopic reflectometers are illustrated inU.S. Pat. No. 4,999,014 to Gold et al., and U.S. Pat. No. 5,747,813 toNorton et al. and are incorporated by reference as if fully set forthherein. Second illumination system 250 may include light source 258 suchas xenon arc lamp. Light source 258 may also include any light sourceconfigured to emit broadband light, which may include visible andultraviolet light. Second illumination system 250 may also be coupled tobeam splitter 259. Beam splitter 259 may be configured to direct lightemitted by light source 258 to a surface of specimen 246 such that asubstantially continuous broadband spectrum of light may be directed tothe surface of specimen 246.

The sample beam may be focused onto a region of specimen 246, and atleast a portion of the sample beam reflected from the illuminated regionmay be passed through a spectrometer (not shown) of detection system252. In addition, detection system 252 may include a diffraction grating(not shown) configured to disperse light passing therethrough as itenters the spectrometer. In this manner, a resulting first orderdiffraction beam may be collected by detector 260 or detector 262, whichmay include a linear photodiode array. The photodiode array, therefore,may measure a sample reflectance spectrum. A relative reflectance may beobtained by dividing the sample light intensity at each wavelength by arelative reference intensity at each wavelength. A relative reflectancespectrum may be used to determine the thickness of one or more layers onthe specimen. In addition, reflectance at a single wavelength and arefractive index of one or more layers may also be determined from therelative reflectance spectrum.

Furthermore, a model method by modal expansion (“MMME”) model may beused to generate a library of various reflectance spectrums. Asdescribed herein, the MMME model is a rigorous diffraction model thatmay be used to determine the theoretical diffracted light “fingerprint”from each grating in the parameter space. Alternative models may also beused to calculate the theoretical diffracted light such as a rigorouscoupling waveguide analysis (“RCWA”) model. The measured reflectancespectrum may be fitted to the library of various reflectance spectrums.

The polarization state and the intensity of light propagating from asurface of specimen 246 may be altered during formation of a layer onspecimen 246. For example, during a deposition process, such as chemicalvapor deposition (“CVD”) and low pressure chemical vapor deposition(“LPCVD”) processes, a layer may be formed on specimen 246 byintroducing reactant gases such as silane, chlorosilane, nitrogen and/orammonia in the process chamber. The reactant gases may decompose andreact at a heated surface of a specimen to form a deposited layer ofmaterial. In this manner, a thickness of the layer being formed on asurface of specimen 246 may increase during the deposition process.

As the thickness of the layer increases during the deposition process,the reflectivity of the surface of the layer may vary approximatelysinusoidally with variations in the thickness of the layer. Therefore,the intensity of the returned light may vary depending on a thickness ofthe deposited layer. In addition, the intensity of the returned lightmay be approximately equal to the square of the field magnitudeaccording to the equation: I_(r)=|E_(R)|². I_(r) can also be expressedin terms of the ellipsometric parameters, ψ and δ. For very thin layers,tan ψ may be independent of thickness, and δ is linearly proportional tothe thickness of the layer. In this manner, one or more output signalsresponsive to the intensity of the light returned from the specimengenerated by the measurement device may be used to determine a thicknessof the layer.

In addition, thickness variations of a layer on a specimen may varydepending on, for example, parameters of an instrument coupled to thedeposition tool. Parameters of an instrument coupled to the depositiontool may determine the process conditions of a deposition process. Forexample, a deposition rate may be defined as a thickness of a layerformed on a surface of a specimen in a period of time. The depositionrate, therefore, may affect variations in the thickness of a layer on aspecimen during a deposition process. A deposition rate may besubstantially constant throughout a deposition process. Alternatively, adeposition rate may vary throughout a deposition process. The depositionrate may vary depending on a number of parameters of one or moreinstruments coupled to the deposition tool that may include, but are notlimited to, temperature within the process chamber, temperaturegradients in the process chamber, pressure within the process chamber,total flow rates of the reactant gases, reactant gas ratios, and a flowrate of one or more dopant gases. In this manner, intensity variationsof light propagating from a surface of the specimen may vary dependingupon parameters of an instrument coupled to the deposition tool.Therefore, a processor coupled to a measurement device may be configuredto determine a parameter of an instrument coupled to a deposition toolfrom the measured intensity variations of the light propagating from asurface of the specimen during a deposition process.

In an embodiment, a processor coupled to a measurement device, as shownin FIG. 23, may be configured to determine a property of a layer formedon a specimen from detected light. The measurement device may beconfigured as described in above embodiments. The property of the formedlayer may include, but is not limited to, a thickness, an index ofrefraction, an extinction coefficient, a critical dimension, or anycombination thereof. Subsequent to a deposition process, the specimenmay be polished such that an upper surface of the deposited material maybe substantially planar. Subsequent to polishing, a layer of resist maybe formed on the deposited layer and the layer of resist may be exposedto pattern the resist during a lithography process. In this manner,selected regions of the deposited layer may be exposed, and at least aportion of the selected regions may be removed in an etch process. Aconductive material such as aluminum or copper may be deposited in theetched portions of the deposited layer and on an upper surface of thedeposited layer, for example, by a physical vapor deposition process.The specimen may be polished such that an upper surface of the specimenmay be substantially planar. In this manner, a number of semiconductorfeatures such as interlevel contact structures may be formed on thespecimen.

The properties of the semiconductor features formed on the specimen mayvary depending upon, for example, properties of the deposited layer andthe conductive material and process conditions of the deposition,polishing, lithography, etch, and physical vapor deposition processes.As such, properties of semiconductor features on a specimen may bedetermined using the determined properties of the deposited layer. Inaddition, a processor coupled to the measurement device may also beconfigured to determine a presence of defects such as foreign materialon the deposited layer prior to, during, or subsequent to the depositionprocess from the detected light.

In an additional embodiment, processor 270, as shown in FIG. 23, may becoupled to measurement device 238 and deposition tool 240. The processormay be configured to interface with the measurement device and thedeposition tool. For example, the processor may receive one or moresignals from the deposition tool during a deposition process. Thesignals may be representative of a parameter of one or more instrumentscoupled to the deposition tool. The processor may also be configured toreceive one or more signals from the measurement device. Signals fromthe measurement device may be representative of the detected light fromdetector 256, 260, and 262 as described herein. In an additionalembodiment, measurement device 238 may be configured, as describedherein, to measure variations in the intensity of light propagating fromthe specimen during a deposition process. For example, measurementdevice 238 may be configured to measure the intensity of lightpropagating from the specimen substantially continuously or atpredetermined time intervals during a deposition process. The processormay, therefore, be configured to monitor variations in output signalsfrom the measurement device during a deposition process. In this manner,the processor may be configured to determine a relationship between themonitored variations and/or the output signals from the measurementdevice and output signals from the deposition tool responsive to aparameter of one or more instruments coupled to the deposition tool. Assuch, the processor may be configured to alter a parameter of one ormore instruments coupled to the deposition tool using the determinedrelationship. In addition, the processor may be configured to determinea parameter of one or more instruments using the determined relationshipand one or more output signals from the measurement device.

Additionally, the processor may be further configured to control themeasurement device and the deposition tool. For example, the processormay be configured to alter a parameter of an instrument coupled to thedeposition tool in response to the detected light. In this manner, theprocessor may be configured to alter a parameter of an instrumentcoupled to the deposition tool using an in situ control technique. Inaddition, the processor may be configured to alter a parameter of aninstrument coupled to the measurement device in response to the detectedlight. For example, the processing device may be configured to alter asampling frequency of the measurement device in response to the detectedlight.

By analyzing variations in output signals from the measurement deviceduring a deposition process, processor 270 may also generate asignature, which may be representative of the formation of a layer onspecimen 246. The signature may include at least one singularity thatmay be characteristic of an endpoint of the deposition process. Forexample, an appropriate endpoint for a deposition process may be apredetermined thickness of a layer on the specimen. A predeterminedthickness of a layer on the specimen may be larger or smaller dependingupon, for example, the semiconductor device fabricated by the depositionprocess. After the processor has detected the singularity of thesignature, the processor may be configured to reduce, and eventerminate, deposition of the layer on the specimen by altering aparameter of an instrument coupled to the deposition tool.

In an embodiment, processor 270 may be configured to use one or moreoutput signals from measurement device 238 to determine a parameter ofone or more instruments coupled to deposition tool 240 for deposition oflayers on additional specimens. For example, a thickness of a layer on aspecimen may be determined using one or more output signals frommeasurement device 238. The thickness of the layer on the specimen maybe greater than a predetermined thickness. Therefore, before processingadditional specimens, a flow rate of a reactant gas or another parameterof one or more instruments coupled to the deposition tool may bealtered. In this manner, a thickness of layers formed on the additionalspecimens may be closer to the predetermined thickness than the measuredlayer. For example, the flow rate of the reactant gas used in thedeposition process may be decreased to deposit a thinner layer on theadditional specimens. In this manner, the processor may be used to altera parameter of one or more instruments coupled to a deposition tool inresponse to one or more output signals of the measurement device using afeedback control technique.

In an additional embodiment, processor 270 may be configured todetermine a parameter of one or more instruments coupled to a processtool, configured to perform additional semiconductor fabricationprocesses, using one or more output signals from measurement device 238.The additional semiconductor fabrication processes may be performedsubsequent to a deposition process. Additional semiconductor fabricationprocesses performed subsequent to a deposition process may include, butare not limited to, a chemical-mechanical polishing process configuredto planarize a deposited layer on the specimen. For example, a thicknessof a layer deposited on a specimen during a deposition process may bedetermined using one or more output signals from the measurement device.The determined thickness of the deposited layer may be greater than apredetermined thickness for the layer.

Process conditions of a subsequent polishing process, however, may beoptimized for the predetermined thickness of the deposited layer on thespecimen. Therefore, before polishing the deposited layer, a parameterof one or more instruments coupled to a polishing tool such as processtime or pressure applied to a back side of the specimen may be alteredsuch that an upper surface of the deposited layer may be planarized. Forexample, a process time may be increased to ensure substantiallycomplete planarization of the deposited layer. In this manner, theprocessor may be configured to alter a parameter of an instrumentcoupled to a chemical mechanical polishing tool in response to one ormore output signals from the measurement device using a feedforwardcontrol technique. In addition, the processor and the measurement devicemay be further configured according to any of the embodiments describedherein. For example, a processor coupled to the measurement device mayalso be configured to detect defects on the specimen, a thickness of adeposited material, a sheet resistivity of a deposited material, athermal diffusivity of a deposited material, or any combination thereofduring the deposition process using one or more output signals from themeasurement device.

In an embodiment, a method for determining a characteristic of aspecimen during a deposition process may include disposing the specimenupon a stage. The stage may be disposed within a process chamber of adeposition tool, as shown in FIG. 23. The stage may also be configuredto support the specimen during a deposition process. The measurementdevice may be coupled to the deposition tool, as shown in FIG. 23. Assuch, the stage may be coupled to a measurement device. In addition, themeasurement device may be configured as described in above embodiments.The method may include directing light to a surface of the specimen. Thedirected light may have a known polarization state. The directed lightmay strike the surface of the specimen. A layer may be formed on thesurface of the specimen during the deposition process.

In addition, the method may include detecting light propagating from thesurface of the specimen during the deposition process. The method mayalso include generating one or more output signals responsive to anintensity and/or a polarization state of the detected light. Theintensity and/or polarization state of the detected light may varydepending on, for example, one or more characteristics of a layer formedon the specimen. Therefore, such one or more output signals may be usedto determine one or more characteristics of the formed layer. In thismanner, the method may include determining one or more characteristicsof a layer being formed on a specimen. Furthermore, the method mayinclude determining one or more characteristics of more than one layerbeing formed on the specimen. The one or more characteristics mayinclude, but are not limited to, a thickness, an index of refraction, anextinction coefficient of one or more layers on the specimen, a criticaldimension of a feature on the specimen, a presence of defects on thespecimen, or any combination thereof.

In additional embodiments, the method for determining a characteristicof a layer on a specimen during a deposition process may include stepsof any methods as described herein. For example, the method may includealtering a parameter of an instrument coupled to the deposition tool inresponse to one or more output signals responsive to an intensity and/ora polarization state of the detected light. In this manner, the methodmay include altering a parameter of an instrument coupled to thedeposition tool using a feedback control technique, an in situ controltechnique, or a feedforward control technique. In addition, the methodmay include altering a parameter of an instrument coupled to themeasurement device in response to the one or more output signals. Forexample, the method may include altering a sampling frequency of themeasurement device in response to the one or more output signals.Furthermore, the method may include obtaining a signature characterizingdeposition of a layer on the specimen. The signature may include atleast one singularity representative of an endpoint of the depositionprocess. For example, an appropriate endpoint for a deposition processmay be a predetermined thickness of a layer formed on the specimen. Inaddition, the predetermined thickness may be larger or smaller dependingupon, for example, the semiconductor device feature fabricated by thedeposition process. Subsequent to obtaining the singularityrepresentative of the endpoint, the method may include altering aparameter of an instrument coupled to the deposition tool to reduce, andeven terminate, the deposition process.

In an embodiment, a computer-implemented method may be used to control asystem configured to determine a characteristic of a layer during adeposition process. The system may include a measurement device coupledto a deposition tool, as described herein. The method may includecontrolling the measurement device. Controlling the measurement devicemay include controlling a light source to direct light to a surface ofthe specimen such that the directed light may strike the surface of thespecimen. The directed light may have a known polarization state. Inaddition, controlling the measurement device may include controlling adetector to detect light propagating from the surface of the specimenduring the deposition process. Furthermore, the method may includeprocessing the detected light to determine an intensity or apolarization state of the detected light. For example, the method mayinclude processing the detected light and generating one or more outputsignals responsive to the detected light. The method may further includedetermining one or more characteristics of a layer being formed on thespecimen using the one or more output signals. The one or morecharacteristics may include a thickness, an index of refraction, and anextinction coefficient of the layer on the specimen, a criticaldimension of a feature on the specimen, a presence of defects on thespecimen, or any combination thereof.

In additional embodiments, the computer-implemented method forcontrolling a system to determine a characteristic of a layer beingformed on a specimen during a deposition process may include steps ofany of the methods as described herein. For example, the method mayinclude controlling an instrument coupled to the deposition tool toalter a parameter of the instrument in response to the one or moreoutput signals. Controlling an instrument coupled to the deposition toolmay include using a feedback control technique, an in situ controltechnique, and/or a feedforward control technique. In addition, themethod may include controlling an instrument coupled to the measurementdevice to alter a parameter of the instrument in response to the one ormore output signals. For example, the method may include controlling aninstrument coupled to the measurement device to alter a samplingfrequency of the measurement device in response to the one or moreoutput signals.

In an additional example, the computer-implemented method may includecontrolling the measurement device to obtain a signature characterizingdeposition of a layer on the specimen. The signature may include atleast one singularity representative of an endpoint of the depositionprocess. For example, an appropriate endpoint for a deposition processmay be a predetermined thickness of a layer deposited on the specimen.Subsequent to obtaining the singularity representative of the endpoint,the method may include controlling a parameter of an instrument coupledto the deposition tool to alter the parameter of the instrument toreduce, and even terminate, deposition of the layer on the specimen.

An additional embodiment relates to a method for fabricating asemiconductor device. The method may include disposing a specimen suchas a wafer upon a stage. The stage may be disposed within a processchamber of a deposition tool. The stage may be configured to support thespecimen during a deposition process. A measurement device may also becoupled to the process chamber of the deposition tool. In this manner,the stage may be coupled to the measurement device. The method mayfurther include forming a portion of a semiconductor device upon thespecimen. For example, forming a portion of a semiconductor device mayinclude depositing a layer of material on the specimen. Depositing thelayer on the specimen may include forming a layer of a dielectricmaterial over a specimen having a plurality of dies. The plurality ofdies may include repeatable pattern features. For example, the depositedlayer may be used to electrically isolate proximate or adjacent featuresof a semiconductor device that may be formed on the specimen.

The method for fabricating a semiconductor device may also includedirecting light toward a surface of the specimen. The directed light mayhave a known polarization state. The method may also include detectinglight propagating from the surface of the specimen during the depositionprocess. In addition, the method may include determining an intensityand/or a polarization state of the detected light. The intensity and/orthe polarization state of the detected light may vary depending upon,for example, one or more characteristics of a layer formed on thespecimen. The method may also include generating one or more outputsignals responsive to an intensity and/or a polarization state of thedetected light. In this manner, the method may include determining acharacteristic of a layer deposited on the specimen using the one ormore output signals. The characteristic may include a thickness, anindex of refraction, and an extinction coefficient of the layer on thespecimen, a critical dimension of a feature on the specimen, or anycombination thereof.

In additional embodiments, the method for fabricating a semiconductordevice may include steps of any of the methods as described herein. Forexample, the method may include altering a parameter of an instrumentcoupled to the deposition tool in response to the one or more outputsignals. Altering a parameter of an instrument coupled to the depositiontool may include using a feedback control technique, an in situ controltechnique, and/or a feedforward control technique. In addition, themethod may include altering a parameter of an instrument coupled to themeasurement device in response to the one or more output signals. Forexample, the method may include altering a sampling frequency of themeasurement device in response to the one or more output signals.Furthermore, the method may include obtaining a signature characterizingdeposition of a layer on the specimen. The signature may include atleast one singularity representative of an endpoint of the depositionprocess. For example, an appropriate endpoint for a deposition processmay be a predetermined thickness of a layer deposited on the specimen.Subsequent to obtaining the singularity representative of the endpoint,the method may include altering a parameter of an instrument coupled tothe deposition tool to reduce, and even terminate, the depositionprocess.

FIG. 24 illustrates an embodiment of a system configured to evaluate anetch process. In an embodiment, a system configured to evaluate an etchprocess may include measurement device 272 coupled to process chamber274 of an etch tool. Measurement device 272 may be coupled to processchamber 274 such that the measurement device may be external to theprocess chamber. As such, exposure of the measurement device to chemicaland physical conditions within the process chamber may be reduced, andeven eliminated. Furthermore, the measurement device may be externallycoupled to the process chamber such that the measurement device may notalter the operation, performance, or control of the etch process. Forexample, a process chamber may include one or more relatively smallsections of a substantially optically transparent material 276 disposedwithin walls of process chamber 274. The configuration of processchamber 274, however, may determine an appropriate method to couplemeasurement device 272 to the process chamber. For example, theplacement and dimensions of substantially optically transparent materialsections 276 within walls of the process chamber may vary depending on,for example, the configuration of the components within the processchamber.

In an alternative embodiment, measurement device 272 may be disposed ina measurement chamber, as described with respect to and shown in FIG.16. The measurement chamber may be coupled to process chamber 274 of anetch tool, as shown in FIG. 17. For example, the measurement chamber maybe disposed laterally or vertically proximate one or more processchambers of an etch tool. In this manner, a robotic wafer handler of anetch tool, stage 280, or another suitable mechanical device may beconfigured to move specimen 278 to and from the measurement chamber andprocess chambers of the etch tool. In addition, the robotic waferhandler, the stage, or another suitable mechanical device may beconfigured to move specimen 278 between process chambers of the etchtool and the measurement chamber. Measurement device 272 may be furthercoupled to process chamber 272 as further described with respect to FIG.17.

Examples of etch tools are illustrated in U.S. Pat. No. 4,842,683 toCheng et al., U.S. Pat. No. 5,215,619 to Cheng et al., U.S. Pat. No.5,614,060 to Hanawa, U.S. Pat. No. 5,770,099 to Rice et al., U.S. Pat.No. 5,882,165 to Maydan et al., U.S. Pat. No. 5,849,136 to Mintz et al.,U.S. Pat. No. 5,910,011 to Cruse, U.S. Pat. No. 5,926,690 to Toprac etal., U.S. Pat. No. 5,976,310 to Levy, U.S. Pat. No. 6,072,147 toKoshiishi et al., U.S. Pat. No. 6,074,518 to Imafuku et al., U.S. Pat.No. 6,083,363 to Ashtiani et al., U.S. Pat. No. 6,089,181 to Suemasa etal., and U.S. Pat. No. 6,110,287 to Arai et al., and are incorporated byreference as if fully set forth herein. An additional example of ameasurement device coupled to an etch tool is illustrated in PCTApplication No. WO 99/54926 to Grimbergen et al., and is incorporated byreference as if fully set forth herein. In WO 99/54926, a measurementdevice coupled to an etch tool is described as a “reflectance thicknessmeasuring machine,” which is substantially different than a measurementdevice as described herein. An example of an apparatus for estimatingvoltage on a wafer located in a process chamber is illustrated inEuropean Patent Application No. EP 1 072 894 A2 to Loewenhardt et al.,and is incorporated by reference as if fully set forth herein.

Measurement device 272 may be configured to direct an incident beam oflight having a known polarization state to specimen 278 such that aregion of the specimen may be illuminated prior to, during, orsubsequent to an etch process. In addition, the measurement device maybe configured to analyze a polarization state of the light returned fromthe illuminated region of the specimen prior to, during, or subsequentto an etch process. For example, the measurement device may include abeam profile ellipsometer. Additionally, however, measurement device 272may include a spectroscopic beam profile ellipsometer, a nullellipsometer, and/or a spectroscopic ellipsometer. Furthermore,measurement device 272 may be configured as a scatterometer as describedherein.

The relatively small sections of transparent material 276 may transmitan incident beam of light from a light source outside the processchamber to a specimen within the process chamber and a returned lightbeam from specimen 278 to a detector outside the process chamber. Theoptically transparent material may have optical or material propertiessuch that the incident beam of light and the returned light beam maypass through the relatively small sections of transparent materialwithout substantially undesirably altering the optical properties of theincident and returned light beams. In this manner, measurement device272 may be coupled to stage 280 disposed within the process chamber andconfigured to support the specimen 278.

Measurement device 272 may include light source 282 configured togenerate an incident beam of light. Light source 282 may include, forexample, a laser configured to emit light having a known polarizationstate such as a gas laser or a solid state laser diode. Such laserstypically may emit light having a single wavelength of 633 nm and 670nm, respectively. Measurement device 272 may also include polarizationsection 284 which may include, but is not limited to, a linear orcircular polarizer or a birefringent quarter wave plate compensator. Thepolarization section may be configured to convert linear polarized lightinto circularly polarized light. In this manner, an incident beam oflight having a known polarization state may be directed toward thespecimen. In addition, measurement device 272 may include beam splitter286 configured to direct at least a portion of the incident beam oflight to an upper surface of specimen 278. Beam splitter 286 may also beconfigured to direct the incident beam through high numerical aperture(“NA”) lens 288. In this manner, measurement device 272 may beconfigured to direct the incident beam of light to specimen 278 at anumber of angles of incidence. For example, high NA lens 288 may have anumerical aperture of approximately 0.9. The numerical aperture of thelens may be larger or smaller, however, depending on, for example, thenumber of angles of incidence required. In addition, high NA lens 288may be configured to focus the incident beam to a very small spot sizeon the upper surface of specimen 278. In this manner, the incident beammay be directed at a number of angles of incidence to a single featureor region on the specimen. Beam splitter 286 may also be configured totransmit a portion of the incident beam light such that the transmittedportion of the incident beam of light may be configured to strikedetector 283. Detector 283 may be configured to monitor fluctuations inthe output power of light source 282.

Light returned from the surface of specimen 278 may pass back throughhigh NA lens 288 and beam splitter 286 to polarizer 290. Polarizer 290may include, for example, a rotating polarizing filter. The measurementdevice may also include detector 292 configured to measure an intensityof the returned light at a number of angles of incidence. For example,detector 292 may include a diode array that may be radially positionedin a two-dimensional array such that the intensity of returned light maybe measured at a number of angles of incidence.

In an alternative embodiment, light returned from the specimen may passthrough quarter-wave plate 294. The quarter-wave plate may be configuredto retard the phase of one of the polarization states of the returnedlight by about 90 degrees. In such a measurement device, polarizer 290may be configured to cause the two polarization states to interfere.Detector 292 for such a measurement device may include a quad-celldetector having four quadrants. Each quadrant of the detector may beconfigured to generate one or more output signals approximatelyproportional to the magnitude of the power of the returned lightstriking the quadrant of the detector. Each signal may represent anintegration of the intensities of the returned light at different anglesof incidence. Such a quad-cell detector may also be configured tooperate as a full power detector if the one or more output signals fromall of the quadrants are summed.

In each of the embodiments described above, processor 296 may beconfigured to determine a thickness, an index of refraction, anextinction coefficient of the specimen and/or a critical dimension of afeature on the specimen from one or more output signals of detector 292.For example, processor 296 may determine a thickness of a layer or afeature on specimen 278 or a thickness of a feature such as an isolationstructure formed in specimen 278 from one or more output signals ofdetector 292.

In an additional alternative embodiment, light source 282 may beconfigured to generate broadband light having a known polarizationstate. An appropriate light source may include a polychromatic lightsource such as a tungsten halogen lamp. For such a configuration of themeasurement device, light returned from the specimen may be passedthrough a filter (not shown). The filter may be configured to pass lightthrough two quadrants of the filter and to block light through two otherquadrants of the filter. As such, light passed through the filter mayhave an ellipsometric signal, δ, of only one sign, for example,positive. After passing through the filter, the returned light may passthrough a spatial filter (not shown) having a small aperture. Thespatial filter may be configured to limit the wavelength of light thatmay be directed to detector 292. As such, the width of the aperture ofthe spatial filter may be larger or smaller depending on, for example,the desired wavelength resolution.

The measurement device may also include a grating (not shown) configuredto focus the returned light such that light from all angles of incidencemay be combined and to angularly disperse the returned light as afunction of wavelength. The grating may include a curved grating and acurved mirror, a lens and a separate planar grating, or a prism.Detector 292 may include an array of a plurality of individual detectorelements. In this manner, the detector may be configured to measure anintensity of returned light over a narrow wavelength regime and a numberof angles of incidence. As such, the spatial filter, the grating, andthe detector may have a configuration substantially similar to aconventional spectrophotometer.

The measurement device may be further configured to perform a secondmeasurement of light returned from the surface of the specimen. In thismeasurement, light passed through the filter may have an ellipsometricsignal, δ, opposite to the sign of the light passed through the filterfor the first measurement (i.e., negative). In the additionalembodiments described above, processor 296 may also be configured todetermine a thickness, an index of refraction, an extinction coefficientof the specimen, and/or a critical dimension of a feature on thespecimen from one or more output signals of the detector. For example,the processor may be configured to determine a thickness of a layer onspecimen 278 or a feature such as an isolation structure formed inspecimen 278 from the one or more output signals of the detector.Examples of beam profile ellipsometers are illustrated in U.S. Pat. No.5,042,951 to Gold et al., U.S. Pat. No. 5,181,080 to Fanton et al., U.S.Pat. No. 5,596,411 to Fanton et al., U.S. Pat. No. 5,798,837 to Aspneset al., and U.S. Pat. No. 5,900,939 to Aspnes et al., and areincorporated by reference as if fully set forth herein.

In an additional embodiment, the system may further include acalibration ellipsometer (not shown). The calibration ellipsometer maybe configured to determine a thickness of a reference layer on aspecimen. The thickness of the reference layer may be measured using themeasurement device as described herein. A phase offset of the thicknessmeasurements of the reference layer generated by the calibrationellipsometer and the measurement device may be determined by processor296. The processor may be configured to use the phase offset todetermine additional layer thicknesses from measurements made by themeasurement device. The calibration ellipsometer may also be coupled toprocess chamber 274 of the etch tool. As such, the calibrationellipsometer may be used to reduce, and even eliminate, variations inmeasured ellipsometer parameters. For example, measurements of theellipsometric parameter, δ, may vary due to changing environmentalconditions along one or more optical paths of the measurement device.Such a variation in the ellipsometric parameter, δ, may alter thicknessmeasurements of a layer on a specimen. Therefore, a calibrationellipsometer may be used to reduce, and even eliminate, a drift inthickness measurements of a layer on a specimen.

The polarization state of light returned from a specimen may be alteredduring etching of the specimen. For example, during an etch process suchas a reactive ion etch (“RIE”) or a plasma etch process, a selectivelyexposed layer on the specimen may be removed by chemical reactionsinvolving chemical reactive species of plasma 298 and a surface ofspecimen 278 and ionic species of plasma 298 striking the surface ofspecimen 278. In this manner, a thickness of the selectively exposedlayer may be removed during the etch process. As the thickness of thelayer is reduced during the etch process, the reflectivity of the layermay vary approximately sinusoidally with variations in the thickness ofthe layer. Therefore, the intensity of the returned light may varydepending on a thickness of the selectively exposed layer. In addition,the intensity of the returned light may be approximately equal to thesquare of the field magnitude according to the equation: I_(r)=|E_(R)|².I_(r) can also be expressed in terms of the ellipsometric parameters, Ψand δ. For very thin layers, tan Ψ may be independent of thickness, andδ may be approximately linearly proportional to the thickness of thelayer. In this manner, output signals from the measurement deviceresponsive to the intensity of the light returned from the specimen maybe used to determine a thickness of the layer.

An etch rate may be defined as a thickness of a layer on a specimen thatmay be removed in a period of time. The etch rate, therefore, maydetermine the variations in the thickness of a layer on a specimenduring an etch process. An etch rate may be substantially constantthroughout an etch process. Alternatively, an etch rate may varythroughout an etch process. For example, an etch rate may decreaseexponentially throughout an etch process. The etch rate may bedetermined by a number of parameters of one or more instruments coupledto the etch tool. For example, one parameter may include a flow rate ofetchant gases from gas source 300 to process chamber 274 of the etchtool. The flow rate may vary depending upon, for example, a parametersuch as a position or a setting of an instrument such as valve 301. Inaddition, such parameters may also include radio frequency power values,which may be determined by instruments such as power supplies 302 and304 coupled to process chamber 274. An additional parameter may includea pressure within the process chamber and may be determined byinstrument 306, which may be configured as a pressure gauge.

Such parameters may affect thickness variations of a layer on a specimenduring an etch process. For example, as pressure decreases in a processchamber, a thickness of a layer on a specimen may be removed at anincreased rate during the etch process. In this manner, an intensity ofa returned sample beam may vary depending upon a parameter of one ormore instruments coupled to the process chamber of the etch tool.Therefore, processor 296 coupled to measurement device 272 may beconfigured to determine a parameter of an instrument coupled to processchamber 274 of the etch tool from the measured intensity of the returnedsample beam during an etch process.

In an embodiment, processor 296 coupled to measurement device 272 may beconfigured to receive one or more output signals from detector 292. Inaddition, the processor may be configured to determine a property of anetched region of specimen 278 from the one or more output signals.Measurement device 272 may be configured as described herein. Forexample, measurement device 272 may be configured as a beam profileellipsometer, a spectroscopic beam profile ellipsometer, a nullellipsometer, a spectroscopic ellipsometer and/or a scatterometer asdescribed herein. Therefore, property of the etched region may include,but is not limited to, a thickness, an index of refraction, anextinction coefficient, a critical dimension of a feature on thespecimen, or any combination thereof. Thickness, index of refraction,and/or extinction coefficient may be commonly referred to as “thin film”characteristics.

Subsequent to an etch process, a specimen may be stripped to removeresidual masking material from the specimen. In addition, a materialsuch as a conductive material may be deposited upon the specimen. Thespecimen may also be polished such that an upper surface of the specimenmay be substantially planar. In this manner, a number of semiconductorfeatures such as interlevel contact structures may be formed on thespecimen. The properties of the semiconductor features formed on thespecimen may vary depending on, for example, one or more properties ofthe etched region and process conditions of the stripping, deposition,and polishing processes. As such, properties of a semiconductor featureon specimen 278 may be determined using the determined properties of theetched region. In addition, processor 296 coupled to measurement device272 may also be configured to determine a presence of defects such asforeign material on the specimen, prior to, during, or subsequent to theetch process from one or more output signals from detector 292.

In an additional embodiment, processor 296 may be coupled to measurementdevice 272 and process chamber 274 of an etch tool. Processor 296 may beconfigured to interface with measurement device 272 and process chamber274. For example, processor 296 may receive one or more output signalsfrom a device coupled to process chamber 274 during an etch process.Such one or more output signals may be responsive to a parameter of aninstrument coupled to the process chamber such as pressure gauge 306.Processor 296 may also be configured to receive one or more outputsignals from detector 292 as described herein.

In an additional embodiment, the measurement device may be configured,as described above, to measure variations in the intensity of lightreturned from the specimen during an etch process. For example, themeasurement device may be configured to measure the intensity of lightreturned from the specimen substantially continuously or atpredetermined time intervals during an etch process. The processor may,therefore, receive output signals responsive to the intensity of lightreturned from the specimen from the measurement device and may monitorvariations in the output signals during an etch process. In addition,processor 296 may be configured to determine a relationship between theoutput signals from measurement device 272 and a parameter of one ormore instruments coupled to process chamber 274. As such, processor 296may be configured to alter a parameter of one or more instrumentscoupled to process chamber 274 in response to the determinedrelationship. In addition, the processor may be configured to determinea parameter of the instrument using the relationship and one or moreoutput signals from the measurement device.

Additionally, processor 296 may be further configured to controlmeasurement device 272 and etch tool 274. For example, the processor maybe configured to alter a parameter of an instrument coupled to the etchtool in response to one or more output signals from the measurementdevice. The processor may be configured to alter a parameter of aninstrument coupled to the etch tool using a feedback control technique,an in situ control technique, and/or a feedforward control technique. Inaddition, the processor may be configured to alter a parameter of aninstrument coupled to the measurement device in response to one or moreoutput signals from the measurement device. For example, the processormay be configured to alter a sampling frequency of the measurementdevice in response to the output signals from the measurement device, asdescribed herein.

By analyzing variations in output signals from the measurement deviceduring an etch process, the processor may also generate a signature thatmay be responsive to the etch process. The signature may include atleast one singularity that may be characteristic of an endpoint of theetch process. For example, an endpoint for an etch process may be apredetermined thickness of a layer on the specimen. A predeterminedthickness of a layer on the specimen may be larger or smaller dependingupon, for example, a semiconductor device being fabricated on thespecimen. In addition, an endpoint for an etch process may beapproximately complete removal of a layer on a specimen. Such anendpoint may correspond to etching through substantially an entirethickness of a layer such that an underlying layer of material may beexposed for subsequent processing. After the processor has detected thesingularity of the signature, the processor may reduce, and eventerminate, etching of the specimen by altering a parameter of aninstrument coupled to the etch tool. A method for detecting an endpointof an etch process is illustrated in PCT Application Nos. WO 00/03421 toSui et al. and WO 00/60657 to Grimbergen et al., and is incorporated byreference as if fully set forth herein.

In an embodiment, the processor may be configured to determine aparameter of one or more instruments coupled to the etch tool forsubsequent etch processes of additional specimens using one or moreoutput signals from the measurement device. For example, a thickness ofa layer on the specimen may be determined using one or more outputsignals from the measurement device. The thickness of the layer on thespecimen may be, for example, greater than a predetermined thickness.The predetermined thickness may vary depending on, for example, afeature of a semiconductor device, which may be fabricated during theetch process. Before processing additional specimens, a radio frequencypower or another parameter of one or more instruments coupled to theetch tool may be altered. For example, the radio frequency power of theetch process may be increased to etch a greater thickness of a layer onadditional specimens. In this manner, a thickness of a layer onadditional specimens etched by the etch process may be closer to thepredetermined thickness than the layer measured on the specimen. In thismanner, the processor may be configured to alter a parameter of one ormore instruments coupled to an etch tool in response to output signalsfrom the measurement device using a feedback control technique.

In an additional embodiment, the processor may be configured todetermine process conditions of additional semiconductor fabricationprocesses using one or more output signals from the measurement device.The additional semiconductor fabrication processes may be performedsubsequent to an etch process. Additional semiconductor fabricationprocesses performed subsequent to the etch process may include, but arenot limited to, a process to strip a masking material on the specimen.Typically, a masking material may be patterned on a specimen using alithography process such that regions of the specimen may be exposedduring subsequent processing. At least a portion of the exposed regionsof the specimen may be removed during a subsequent etch process.

Masking material remaining on the specimen after the etch process may beremoved by a stripping process. A thickness of a masking material on aspecimen during or subsequent to an etch process may be determined usingone or more output signals from the measurement device. The determinedthickness of the masking material on the specimen subsequent to an etchprocess may be, for example, greater than a predetermined thickness.Current process conditions of a stripping process, however, may beoptimized for the predetermined thickness of the masking material on thespecimen. Therefore, before stripping the masking material, a processcondition of the stripping process such as process time or processtemperature may be altered such that substantially the entire maskingmaterial may be removed by the stripping process. For example, a processtime of the stripping process may be increased such that approximatelyan entire thickness of the masking material may be removed from thespecimen. In this manner, the processor may be configured to alter aparameter of an instrument coupled to a stripping tool in response toone or more output signals from the measurement device using afeedforward control technique. In addition, the processor may be furtherconfigured according to any of the embodiments described herein.

In an embodiment, a method for determining a characteristic of aspecimen during an etch process may include disposing specimen 278 uponstage 280. Stage 280 may be disposed within process chamber 274 of anetch tool. The stage may be configured to support the specimen during anetch process. Measurement device 272 may be coupled to process chamber274 of the etch tool as described herein. As such, stage 280 may becoupled to measurement device 272. In addition, measurement device 272may be configured as described herein. The method may include directingan incident beam of light to a region of the specimen. The incident beamof light may have a known polarization state. The directed incident beamof light may illuminate the region of the specimen at multiple angles ofincidence during the etch process. The illuminated region of thespecimen may be an exposed region of the specimen being removed duringthe etch process.

In addition, the method may include detecting light returned from theilluminated region of the specimen during the etch process. The methodmay also include generating one or more output signals in response tothe detected light. The one or more output signals may be responsive toa polarization state of the light returned from the illuminated regionof the specimen. Therefore, the method may include determining a changein a polarization state of the incident beam of light returned from thespecimen. The change in the polarization state of the incident beam oflight returned from the specimen may vary depending upon, for example,one or more characteristics of the specimen such as a thickness of alayer on the specimen. In this manner, the method may includedetermining one or more characteristics of a layer on the specimen usingthe one or more output signals. Furthermore, the method may includedetermining one or more characteristics of more than one layer on thespecimen using the one or more output signals. Such characteristics mayinclude a thickness, an index of refraction, and an extinctioncoefficient of the layer on the specimen, a critical dimension of afeature on the specimen, or any combination thereof.

In additional embodiments, the method for determining a characteristicof a layer on a specimen during an etch process may include any steps ofthe embodiments as described herein. For example, the method may includealtering a parameter of one or more instruments coupled to the etch toolin response to one or more output signals from the measurement device.In this manner, the method may include altering a parameter of one ormore instruments coupled to the etch tool using a feedback controltechnique, an in situ control technique, and/or a feedforward controltechnique. In addition, the method may include altering a parameter ofone or more instruments coupled to the measurement device in response toone or more output signals from the measurement device. For example, themethod may include altering a sampling frequency of the measurementdevice in response to one or more output signals from the measurementdevice.

Furthermore, the method may include obtaining a signature characterizingan etch process. The signature may include at least one singularityrepresentative of an endpoint of the etch process. For example, anendpoint of an etch process may be a predetermined thickness of a layeron the specimen. In addition, the predetermined thickness may be largeror smaller depending upon, for example, a semiconductor device beingfabricated on the specimen. Subsequent to obtaining the singularityrepresentative of the endpoint, the method may include altering aparameter of one or more instruments coupled to the etch tool to reduce,and even terminate, the etch process.

An additional embodiment relates to a computer-implemented method forcontrolling a system configured to determine a characteristic of aspecimen during an etch process. The system may include a measurementdevice coupled to an etch tool as described herein. The method mayinclude controlling the measurement device to detect light returned froma region of the specimen during an etch process. For example,controlling the measurement device may include controlling a lightsource to direct an incident beam of light to a region of the specimenduring an etch process. The light source may be controlled such that theincident beam of light may illuminate the region of the specimen atmultiple angles of incidence during the etch process. The incident beamof light may have a known polarization state. The illuminated region ofthe specimen may include a region of the specimen being removed duringthe etch process. In addition, controlling the measurement device mayinclude controlling a detector to detect at least a portion of lightreturned from the illuminated region of the specimen during the etchprocess. The method may also include generating one or more outputsignals responsive to the detected light. Furthermore, the method mayinclude processing the one or more output signals to determine a changein a polarization state of the incidence beam of light returned from theilluminated region of the specimen. The method may further includedetermining one or more characteristics of a layer on the specimen usingthe one or more output signals. The characteristics may include, but arenot limited to, a thickness, an index of refraction, an extinctioncoefficient of the layer on the specimen, and/or a critical dimension ofa feature on the specimen, or any combination thereof.

In additional embodiments, the computer-implemented method forcontrolling a system configured to determine a characteristic of aspecimen during an etch process may include steps of any of theembodiments as described herein. For example, the method may includecontrolling an instrument coupled to the etch tool to alter a parameterof the instrument in response to one or more output signals from themeasurement device. The method may include controlling an instrumentcoupled to the etch tool to alter a parameter of the instrument using afeedback control technique, an in situ control technique, and/or afeedforward control technique. In addition, the method may includecontrolling an instrument coupled to the measurement device to alter aparameter of the instrument in response to one or more output signalsfrom the measurement device. For example, the method may includecontrolling an instrument coupled to the measurement device to alter asampling frequency of the measurement device in response to one or moreoutput signals from the measurement device.

In an additional example, the method may include controlling themeasurement device to obtain a signature characteristic of an etchprocess. The signature may include at least one singularityrepresentative of an endpoint of the etch process. An endpoint of anetch process may include, but is not limited to, a predeterminedthickness of a layer on the specimen. The predetermined thickness may belarger or smaller depending upon, for example, a semiconductor devicebeing fabricated on the specimen. Subsequent to obtaining thesingularity representative of the endpoint, the method may includecontrolling a parameter of one or more instruments coupled to the etchtool to alter a parameter of the instruments to reduce, and even end,the etch process.

An additional embodiment relates to a method for fabricating asemiconductor device, which may include disposing a specimen upon astage. The stage may be disposed within a process chamber of an etchtool, as shown in FIG. 24. The stage may be configured to support thespecimen during an etch process. A measurement device may also becoupled to the process chamber of the etch tool, as shown in FIG. 24. Inthis manner, the stage may be coupled to the measurement device.

The method may further include forming a portion of a semiconductordevice upon the specimen. For example, forming a portion of asemiconductor device may include etching exposed regions of thespecimen. During an etch process, typically, an entire specimen may beexposed to an etch chemistry. A masking material may be arranged on thespecimen prior to the etch process to expose predetermined regions ofthe specimen to the etch chemistry. For example, portions of the maskingmaterial may be removed using a lithography process and/or an etchprocess to expose predetermined regions of the specimen. The exposedpredetermined regions may be regions of the specimen in which featuresof a semiconductor device may be formed. Remaining portions of themasking material may substantially inhibit underlying regions of thespecimen to be etched during the etch process. Appropriate maskingmaterials may include, but are not limited to, a resist, a dielectricmaterial such as silicon oxide, silicon nitride, and titanium nitride, aconductive material such polycrystalline silicon, cobalt silicide, andtitanium silicide, or any combination thereof.

The method for fabricating a semiconductor device may also includedirecting an incident beam of light to a region of the specimen. Theincident beam of light may have a known polarization state. The regionof the specimen may be a region of the specimen being removed during theetch process. The method may also include detecting at least a portionof the light returned from the illuminated region of the specimen duringthe etch process. The method may further include generating a signalresponsive to the detected light. In addition, the method may includedetermining a change in a polarization state of the incident beam oflight returned from the specimen. The change in the polarization stateof the incident beam of light returned from the specimen may varydepending on, for example, one or more characteristics of the specimen.In this manner, the method may include determining one or morecharacteristics of a layer on the specimen using the one or more outputsignals. The characteristics may include, but are not limited to, athickness, an index of refraction, and an extinction coefficient of thelayer on the specimen, a critical dimension of a feature on thespecimen, or any combination thereof.

In additional embodiments, the method for fabricating a semiconductordevice may include steps of any of the embodiments as described herein.For example, the method may include altering a parameter of one or moreinstruments coupled to the etch tool in response to one or more outputsignals from the measurement device. In this manner, the method mayinclude altering a parameter of one or more instruments coupled to theetch tool using a feedback control technique, an in situ controltechnique, and/or a feedforward control technique. In addition, themethod may include altering a parameter of one or more instrumentscoupled to the measurement device in response to one or more outputsignals from the measurement device. For example, the method may includealtering a sampling frequency of the measurement device in response toone or more output signals from the measurement device.

Furthermore, the method may include obtaining a signature characteristicof an etch process. The signature may include at least one singularityrepresentative of an endpoint of the etch process. An endpoint of anetch process may be a predetermined thickness of a layer on thespecimen. In addition, the predetermined thickness may be larger orsmaller depending upon, for example, the semiconductor device beingfabricated on the specimen. Subsequent to obtaining the singularityrepresentative of the endpoint, the method may include altering aparameter of one or more instruments coupled to the etch tool to reduce,and even terminate, the etch process.

FIG. 25 illustrates an embodiment of a system configured to evaluate anion implantation process. In an embodiment, a system configured toevaluate an ion implantation process may include measurement device 308coupled to ion implanter 310. Measurement device 308 may be coupled toion implanter 310 such that measurement device 308 may be external tothe ion implanter. As such, exposure of the measurement device tochemical and physical conditions within the ion implanter may bereduced, and even eliminated. Furthermore, measurement device 308 may beexternally coupled to ion implanter 310 such that the measurement devicedoes not alter the operation, performance, or control of the ionimplantation process. For example, an ion implanter process chamber mayinclude relatively small sections of a substantially transparentmaterial 312 disposed within walls of the process chamber. Aconfiguration of an ion implanter, however, may determine an appropriatemethod to couple the measurement device to the ion implanter. Forexample, the placement and dimensions of the substantially transparentmaterial sections 312 within walls of the process chamber may varydepending on the configuration of the components within the processchamber. Examples of ion implanters are illustrated in U.S. Pat. No.4,578,589 to Aitken, U.S. Pat. No. 4,587,432 to Aitken, U.S. Pat. No.4,733,091 to Robinson et al., U.S. Pat. No. 4,743,767 to Plumb et al.,U.S. Pat. No. 5,047,648 to Fishkin et al., U.S. Pat. No. 5,641,969 toCooke et al., U.S. Pat. No. 5,886,355 to Bright et al., U.S. Pat. No.5,920,076 to Burgin et al., U.S. Pat. No. 6,060,715 to England et al.,U.S. Pat. No. 6,093,625 to Wagner et al., and U.S. Pat. No. 6,101,971 toDenholm et al., and are incorporated by reference as if fully set forthherein.

In an alternative embodiment, measurement device 308 may be disposed ina measurement chamber, as described with respect to and shown in FIG.16. The measurement chamber may be coupled to ion implanter 310, asshown in FIG. 17. For example, the measurement chamber may be disposedlaterally or vertically proximate one or more process chambers of ionimplanter 310. In this manner, a robotic wafer handler of ion implanter310, stage 316, or another suitable mechanical device may be configuredto move specimen 314 to and from the measurement chamber and processchambers of the ion implanter. In addition, the robotic wafer handler,the stage, or another suitable mechanical device may be configured tomove specimen 314 between process chambers of the ion implanter and themeasurement chamber. Measurement device 308 may be further coupled toion implanter 310 as further described with respect to FIG. 17.

Measurement device 308 may be configured to periodically direct anincident beam of light to specimen 314 such that a region of thespecimen may be periodically excited prior to, during, and/or subsequentto ion implantation. Measurement device 308 may also be configured todirect a sample beam of light to the periodically excited region ofspecimen 314 prior to, during, and/or subsequent to ion implantation. Inaddition, measurement device 308 may be configured to measure anintensity of the sample beam reflected from the periodically excitedregion of specimen 314 prior to, during, and/or subsequent to ionimplantation. The small sections of substantially transparent material312 may transmit the incident and sample beams from one or moreillumination systems outside the process chamber to a specimen withinthe process chamber and the reflected sample beam from the specimen to adetection system outside the process chamber. The substantiallytransparent material 312 may have optical and/or material propertiessuch that the beams may pass through the substantially transparentsections of the process chamber without undesirably altering the opticalproperties of the incident, sample, and reflected beam. In this manner,measurement device 308 may be coupled to stage 316 disposed within theprocess chamber and configured to support specimen 314.

In an embodiment, measurement device 308 may include light source 318such as an argon laser configured to emit an incident beam of light. Thelight source may also be configured to generate electromagneticradiation of other and/or multiple wavelengths including X-rays, gammarays, infrared light, ultraviolet light, visible light, microwaves, orradio-frequencies. Light source 318 may also include any energy sourcethat may cause a localized heated area on a surface of specimen 314 suchas a beam of electrons, protons, neutrons, ions, or molecules. Such anenergy source may be disposed within the process chamber of ionimplanter 310. In addition, light source 318 may also include any energysource configured to cause at least some electrons of the specimen in avalence band to be excited across the band gap to a conductor bandthereby creating a plurality of electron-hole pairs called a plasma.Measurement device 308 may also include modulator 320, which may beconfigured to chop the incident beam emitted from light source 318. Themodulated incident light beam may be directed to specimen 314 toperiodically excite a region of the specimen.

Measurement device 308 may also include additional light source 322 suchas a helium neon laser configured to emit a sample beam of light. Themeasurement device may further include additional optical componentssuch as dichroic mirror 324, polarizing beamsplitter 326, quarter waveplate 328, and focusing lens 330 such as a microscopic objective. Theadditional optical components may be arranged within the measurementdevice such that the modulated incident beam and the sample beam may bedirected to substantially the same region of the specimen. Theadditional optical components, however, may also be arranged within themeasurement device such that the modulated incident beam and the samplebeam may be directed to two overlapping but non-coaxial, or twolaterally spaced, regions of the specimen.

Measurement device 308 may also include a tracker (not shown) coupled toeach of the light sources. The trackers may be configured to control aposition of the incident beam and the sample beam. For example, thetrackers may be configured to alter a position of the incident beam withrespect to a position of the sample beam during an ion implantationprocess. In addition, the trackers may be configured to controlpositions of the incident beam and the sample beam such that the beamsmay be directed to substantially different regions of the specimenduring an ion implantation process. As such, the system may beconfigured to evaluate the ion implantation process at any number ofpositions on the specimen. The additional optical components may also bearranged within the measurement device such that the sample beamreflected from the surface of the specimen may be directed to adetection system of the measurement device.

In an embodiment, detection system 332 may include a conventionalphotodetector that may be configured to measure intensity variations ofthe reflected sample beam. The intensity variations of the reflectedsample beam may vary depending on, for example, periodic reflectivitychanges in the periodically excited region of specimen 314. Inalternative embodiments, detection system 332 may include a conventionalinterferometer. In this manner, the reflected sample beam may becombined with a reference beam prior to striking the interferometer. Thereference beam may be a portion of the sample beam and may be directedto the interferometer by partially transmissive mirror 326. Since thesample beam reflected from the specimen and the reference beam may notbe in phase, interference patterns may develop in the combined beam.Intensity variations of the interference patterns may be detected by theinterferometer.

In additional embodiments, detection system 332 may include a split orbi-cell photodetector having a number of quadrants. Each quadrant of thephotodetector may be configured to independently measure an intensity ofthe reflected sample beam. In this manner, each quadrant may detectdifferent intensities as the reflected sample beam fluctuates across thesurface of the photodetector. As such, the split photodetector may beconfigured to measure the extent of deflection of the reflected samplebeam. For deflection measurements, the modulated incident beam and thesample beam may be directed to two overlapping but non-coaxial regionsof the specimen as described above. Examples of modulated opticalreflectance measurement devices are illustrated in U.S. Pat. No.4,579,463 to Rosencwaig et al., U.S. Pat. No. 4,750,822 to Rosencwaig etal., U.S. Pat. No. 4,854,710 to Opsal et al., and U.S. Pat. No.5,978,074 to Opsal et al. and are incorporated by reference as if fullyset forth herein. The embodiments described herein may also includefeatures of the systems and methods illustrated in these patents. Inaddition, each of the detectors described above may be configured togenerate one or more output signals responsive to the intensityvariations of the reflected sample beam.

The intensity variations of the reflected sample beam may be altered bythe implantation of ions into the specimen. For example, during ionimplantation processes, and especially in processes using high dosagelevels, a portion of the specimen may be damaged due to the implantationof ions into the specimen. A damaged portion of the specimen may,typically, include an upper crystalline damaged layer and anintermediate layer of amorphous silicon. A lattice structure of theupper crystalline damaged layer may be substantially different than alattice structure of the intermediate layer of amorphous silicon. Theupper crystalline layer and the amorphous layer of silicon may,therefore, act as thermal and optical boundaries. For example, the twolayers may have different periodic excitations due to differences inlattice structure. In addition, the different periodic excitations maycause the two layers to reflect the sample beam in a different manner.As such, the intensity variations of the reflected sample beam maydepend on a thickness and a lattice structure of the upper crystallinelayer and the amorphous layer.

The thickness of the upper crystalline layer and the amorphous layer maydepend on a parameter of one or more instruments coupled to the ionimplanter. A parameter of one or more instruments coupled to the ionimplanter may determine the process conditions of an ion implantationprocess. Instruments coupled to ion implanter may include, but are notlimited to, gas supply 334, energy source 336, pressure valve 338, andmodulator 340. Damage in the upper crystalline layer may vary dependingon, for example, electronic collisions between atoms of the siliconlayer and the implanted ions. Displacement damage, however, may not beproduced if the ions entering the silicon layer do not have enoughenergy per nuclear collision to displace silicon atoms from theirlattice sites. In this manner, a thickness of the upper crystallinelayer may vary depending upon, for example, implant energy. Increasingthe dose of ions, and in particular heavy ions, may produce an amorphousregion below the upper crystalline damaged layer in which the displacedatoms per unit volume may approach the atomic density of thesemiconductor. As the implant dose of an ion implantation processincreases, a thickness of the amorphous layer may also increase. In thismanner, the intensity variations of the reflected sample beam may bedependent upon process conditions during implantation including, but notlimited to, the implant energy and dose. Therefore, processor 342coupled to measurement device 308 may be configured to determine aparameter of an instrument coupled to ion implanter 310 from themeasured intensity variations of the reflected sample beam prior to,during, and/or subsequent to ion implantation. Parameters of one or moreinstruments coupled to the ion implanter may define process conditionsincluding, but not limited to, an implant energy, an implant dose, animplant species, an angle of implantation, and temperature.

In an embodiment, processor 342 coupled to measurement device 308 may beconfigured to determine one or more characteristics of an implantedregion of specimen 314 from one or more output signals from detectionsystem 332 prior to, during, and/or subsequent to ion implantation. Thecharacteristics of an implanted region may include, but are limited to,a presence of implanted ions in the specimen, a concentration ofimplanted ions in the specimen, a depth of implanted ions in thespecimen, a distribution profile of implanted ions in the specimen, orany combination thereof. Subsequent to implantation, the specimen may beannealed to electrically activate implanted regions of the specimen.Characteristics of an electrically activated implanted region such asdepth and distribution profile may depend upon thicknesses of the uppercrystalline layer and the amorphous layer formed during implantation andprocess conditions of the anneal process. As such, characteristics of anelectrically activated implanted region may be determined from thedetermined characteristics of the implanted region. In addition,processor 342 coupled to measurement device 308 may be configured todetermine a presence of defects such as foreign material on the specimenprior to, during, and/or subsequent to an implantation process from oneor more output signals from detection system 332.

In an additional embodiment, processor 342 may be coupled to measurementdevice 308 and ion implanter 310. The processor may be configured tointerface with the measurement device and the ion implanter. Forexample, the processor may receive output signals from the ion implanterduring an ion implantation process that may be representative of aparameter of one or more instruments coupled to the ion implanter. Theprocessor may also be configured to receive output signals from thedetection system during an ion implantation process. In an additionalembodiment, the measurement device may be configured to measurevariations in output signals from the detection system during an ionimplantation process. For example, the measurement device may beconfigured to detect the reflected sample beam substantiallycontinuously or at predetermined time intervals during implantation. Theprocessor may, therefore, be configured to receive output signalsresponsive to the detected light substantially continuously or atpredetermined time intervals and to monitor variations in the one ormore output signals during the ion implantation process. In this manner,processor 342 may be configured to determine a relationship between theoutput signals responsive to the detected light and parameters of one ormore instruments coupled to an ion implanter. As such, processor 342 maybe configured to alter a parameter of one or more instruments inresponse to the determined relationship. In addition, processor 342 maybe configured to determine a parameter of one or more instruments usingthe relationship and output signals from the measurement device.

Furthermore, additional controller computer 344 may be coupled to ionimplanter 310. Controller computer 344 may be configured to alter aparameter of one or more instruments coupled to the ion implanter.Processor 342 may also be coupled to controller computer 344. In thismanner, controller computer 344 may be configured to alter a parameterof one or more instruments coupled to the ion implanter in response toone or more output signals from processor 342, which may be responsiveto a determined parameter. In addition, controller computer 344 maymonitor a parameter of one or more instruments coupled to the ionimplanter and may send one or more output signals responsive to themonitored parameters to processor 342.

Additionally, the processor may be further configured to control themeasurement device and the ion implanter. For example, the processor maybe configured to alter a parameter of one or more instruments coupled tothe ion implanter in response to one or more output signals from themeasurement device. In this manner, the processor may be configured toalter a parameter of an instrument coupled to the ion implanter using afeedback control technique, an in situ control technique, and/or afeedforward control technique. In addition, the processor may beconfigured to alter a parameter of an instrument coupled to themeasurement device in response to output signals from the measurementdevice. For example, the processing device may be configured to alter asampling frequency of the measurement device in response to outputsignals from the measurement device.

By analyzing the variations in output signals from the measurementdevice during an ion implantation process, the processor may alsogenerate a signature that may be representative of the implantation ofthe ions into the specimen. The signature may include at least onesingularity that may be characteristic of an endpoint of the ionimplantation process. For example, an appropriate endpoint for an ionimplantation process may be a predetermined concentration of ions in thespecimen. In addition, the predetermined concentration of ions may belarger or smaller depending upon a semiconductor device being fabricatedon the specimen. After the processor has detected the singularity of thesignature, the processor may reduce, and even terminate, theimplantation of ions into the specimen by altering a parameter of one ormore instruments coupled to the ion implanter.

In an embodiment, the processor may be configured to determineappropriate process conditions for subsequent ion implantation processesof additional specimens using output signals from the measurementdevice. For example, a depth of implanted ions in the specimen may bedetermined using the output signals. The determined depth of animplanted region of the specimen may be less than a predetermined depth.The predetermined depth may vary depending on a semiconductor devicebeing fabricated on the specimen. Before processing additionalspecimens, a parameter of one or more instruments coupled to the ionimplanter may be altered such that an implanted depth of the additionalspecimens may be closer to the predetermined depth than the implanteddepth of the measured specimen. For example, the implant energy of theion implant process may be increased to drive the ions deeper into theadditional specimens. In this manner, the processor may be configured toalter a parameter of one or more instruments coupled to an ion implanterin response to output signals from the measurement device using afeedback control technique.

In an additional embodiment, the processor may be configured todetermine process conditions of additional semiconductor fabricationprocesses that may be performed subsequent to the ion implantationprocess using output signals from the measurement device. Additionalsemiconductor fabrication process may include, but are not limited to, aprocess to anneal implanted regions of the specimen. For example, adepth of an implanted region of a specimen may be determined using theoutput signals. The determined depth of the implanted region of thespecimen may be greater than a predetermined depth. Current processconditions of a subsequent annealing process, however, may be optimizedfor the predetermined depth. Therefore, before annealing the implantedspecimen, a process condition of the annealing process such as annealtime or anneal temperature may be altered. For example, an anneal timemay be increased to ensure substantially complete recrystallization ofthe amorphous layer formed in the specimen. In this manner, theprocessor may be configured to alter a parameter of one or moreinstruments coupled to an anneal tool in response to output signals fromthe measurement device using a feedforward control technique. Inaddition, the processor may be further configured according to any ofthe embodiments as described herein.

In an embodiment, a method for determining a characteristic of aspecimen prior to, during, and/or subsequent to an ion implantationprocess may include disposing the specimen upon a stage. The stage maybe disposed within a process chamber of an ion implanter. The stage mayalso be configured according to any of the embodiments as describedherein. A measurement device may be coupled to the ion implanter asdescribed herein. As such, the stage may be coupled to the measurementdevice. In addition, the measurement device may be configured asdescribed herein.

The method may include directing an incident beam of light to a regionof the specimen to periodically excite a region of the specimen duringthe ion implantation process. The region of the specimen may be a regionof the specimen being implanted during the ion implantation process. Themethod may also include directing a sample beam of light to theperiodically excited region of the specimen during the ion implantationprocess. In addition, the method may include detecting at least aportion of the sample beam reflected from the periodically excitedregion of the specimen during the ion implantation process. The methodmay further include generating one or more output signals in response tothe detected light. Furthermore, the method may include determining oneor more characteristics of the implanted region of the specimen usingthe one or more output signals. The characteristics of the implantedregion may include, but are not limited to, a presence of implanted ionsin the specimen, a concentration of implanted ions in the specimen, adepth of implanted ions in the specimen, a distribution profile ofimplanted ions in the specimen, or any combination thereof.

In additional embodiments, the method for determining a characteristicof a specimen during an ion implantation process may include steps ofany of the embodiments described herein. For example, the method mayinclude altering a parameter of one or more instruments coupled to theion implanter in response to the one or more output signals. In thismanner, the method may include altering a parameter of one or moreinstruments coupled to the ion implanter using a feedback controltechnique, an in situ control technique, and/or a feedforward controltechnique. In addition, the method may include altering a parameter ofone or more instruments coupled to the measurement device in response tothe one or more output signals. For example, the method may includealtering a sampling frequency of the measurement device in response tothe one or more output signals.

The method may further include obtaining a signature characterizing theimplantation of the ions into a specimen. The signature may include atleast one singularity representative of an endpoint of the ionimplantation process. For example, an endpoint for an ion implantationprocess may be a predetermined concentration of ions. In addition, thepredetermined concentration of ions may be larger or smaller dependingupon a semiconductor device being fabricated on the specimen. Subsequentto obtaining the singularity representative of the endpoint, the methodmay include altering a parameter of one or more instruments coupled tothe ion implanter to reduce, and even terminate, the ion implantationprocess.

In an embodiment, a computer-implemented method may be used to control asystem configured to determine a characteristic of a specimen prior to,during, and/or subsequent to an ion implantation process. The system mayinclude a measurement device coupled to an ion implanter as describedherein. The method may include controlling the measurement device tomeasure modulated optical reflectance of a region of a specimen duringthe ion implantation process. For example, controlling the measurementdevice may include controlling a light source to direct an incident beamof light to a region of the specimen such that the region may beperiodically excited during the ion implantation process. Controllingthe measurement device may also include controlling an additional lightsource to direct a sample beam of light to the periodically excitedregion of the specimen during the ion implantation process.

In addition, controlling the measurement device may include controllinga detection system to detect at least a portion of the sample beamreflected from the periodically excited region of the specimen duringthe ion implantation process. In addition, the method may includegenerating one or more output signals in response to the detected light.Furthermore, the method may include processing the one or more outputsignals to determine one or more characteristics of the implanted regionof the specimen. The characteristics of the implanted region mayinclude, but are not limited to, a presence of implanted ions in thespecimen, a concentration of implanted ions in the specimen, a depth ofimplanted ions in the specimen, a distribution profile of implanted ionsin the specimen, or any combination thereof.

In additional embodiments, the computer-implemented method forcontrolling a system to determine a characteristic of a specimen priorto, during, and/or subsequent to an ion implantation process may includesteps of any of the embodiments described herein. For example, themethod may include controlling an instrument coupled to the ionimplanter to alter a parameter of the instrument in response to the oneor more output signals. In this manner, the method may includecontrolling an instrument coupled to the ion implanter to alter aparameter of the instrument using a feedback control technique, an insitu control technique, and/or a feedforward control technique. Inaddition, the method may include controlling an instrument coupled tothe measurement device to alter the parameter in response to the one ormore output signals. For example, the method may include controlling aninstrument coupled to the measurement device to alter a samplingfrequency of the measurement device in response to the one or moreoutput signals. Furthermore, the method may include controllingadditional components of the system. For example, the method may includecontrolling the trackers to control lateral positions of the incidentbeam and the sample beam with respect to the specimen during use. Inthis manner, the method may include controlling the trackers to evaluatethe ion implantation process at any number of positions on the specimen.

In an additional example, the method may include controlling themeasurement device to obtain a signature characterizing the implantationof the ions into the specimen. The signature may include at least onesingularity representative of an endpoint of the ion implantationprocess. For example, an endpoint for an ion implantation process may bea predetermined concentration of ions. The predetermined concentrationof ions may be larger or smaller depending upon, for example, asemiconductor device being fabricated on the specimen. Subsequent toobtaining the singularity representative of the endpoint, the method mayinclude controlling a parameter of an instrument coupled to the ionimplanter to alter the parameter of the instrument thereby reducing, andeven terminating, implantation of ions into the specimen.

An additional embodiment relates to a method for fabricating asemiconductor device that may include disposing a specimen upon a stage.The stage may be disposed within a process chamber of an ion implanter.The stage may be configured as described herein. A measurement devicemay also be coupled to the process chamber of the ion implanter. In thismanner, the stage may also be coupled to the measurement device. Themethod may include forming a portion of the semiconductor device uponthe specimen. For example, forming the portion of the semiconductordevice may include implanting ions into the specimen. During an ionimplantation process, typically, the entire wafer may be scanned with abeam of ions. A masking material may be arranged on the specimen toexpose predetermined regions of the specimen to implantation. Forexample, portions of the masking material may be removed using alithography process and/or an etch process to expose regions of thespecimen to an implantation process. The exposed regions may includeregions of the specimen in which features of a semiconductor device areto be formed. Appropriate masking materials may include, but are notlimited to, a resist, a dielectric material such as silicon oxide,silicon nitride, and titanium nitride, a conductive material such aspolycrystalline silicon, cobalt silicide, and titanium silicide, or anycombination thereof.

The method for fabricating a semiconductor device may also includedirecting an incident beam of light to a region of the specimen. Thedirected incident beam of light may periodically excite a region of thespecimen during the ion implantation process. The region of the specimenmay be a region of the specimen implanted during the ion implantationprocess. The method may also include directing a sample beam of light tothe periodically excited region of the specimen during the ionimplantation process. In addition, the method may include detecting atleast a portion of the sample beam reflected from the periodicallyexcited region of the specimen during the ion implantation process. Themethod may also include generating one or more output signals inresponse to the detected light. Furthermore, the method may includedetermining one or more characteristics of the implanted region of thespecimen using the one or more output signals. The characteristics ofthe implanted region may include, but are not limited to, a presence ofimplanted ions in the specimen, a concentration, a depth, and adistribution profile of implanted ions in the specimen, or anycombination thereof.

In additional embodiments, the method for fabricating a semiconductordevice may include steps of any of the embodiments described herein. Forexample, the method may include altering a parameter of an instrumentcoupled to the ion implanter in response to the one or more outputsignals. In this manner, the method may include altering a parameter ofan instrument coupled to the ion implanter using a feedback controltechnique, an in situ control technique, and/or a feedforward controltechnique. In addition, the method may include altering a parameter ofan instrument coupled to the measurement device in response to the oneor more output signals. For example, the method may include altering asampling frequency of the measurement device in response to the one ormore output signals.

Furthermore, the method may include obtaining a signature characteristicof the implantation of the ions into the specimen. The signature mayinclude at least one singularity representative of an endpoint of theion implantation process. For example, an endpoint for an ionimplantation process may be a predetermined concentration of ions. Inaddition, the predetermined concentration of ions may be larger orsmaller depending upon a semiconductor device being fabricated on thespecimen. Subsequent to obtaining the singularity representative of theendpoint, the method may include altering a parameter of an instrumentcoupled to the ion implanter to reduce, and even terminate, theimplantation of ions into the specimen.

FIG. 26 illustrates an embodiment of a system configured to determine atleast one characteristic of micro defects on a surface of a specimen. Inan embodiment, such a system may include measurement device 346 coupledto process tool 348. Process tool 348 may be configured as a processchamber of a semiconductor fabrication process tool or a semiconductorfabrication process tool. In this manner, process tool 348 may beconfigured to perform a step of a semiconductor fabrication process suchas lithography, etch, ion implantation, chemical-mechanical polishing,plating, chemical vapor deposition, physical vapor deposition, andcleaning. For example, as shown in FIG. 26, process tool 348 may includea resist apply chamber of a process tool or a develop chamber of aprocess tool. As such, process tool 348 may be configured to fabricate aportion of a semiconductor device on specimen.

Measurement device 346 may be coupled to process tool 348 such that themeasurement device may be external to the process tool. As such,exposure of the measurement device to chemical and physical conditionswithin the process tool may be reduced, and even eliminated.Furthermore, the measurement device may be externally coupled to theprocess tool such that the measurement device may not alter theoperation, performance, or control of the process. For example, aprocess tool may include one or more relatively small sections of asubstantially transparent material 350 disposed within walls of theprocess tool. The configuration of process tool 348, however, maydetermine an appropriate method to couple measurement device 346 to theprocess tool. For example, the placement and dimensions of thesubstantially transparent material sections 350 within the walls of theprocess tool may be depend on the configuration of the components withinthe process tool.

In an alternative embodiment, measurement device 346 may be disposed ina measurement chamber, as described with respect to and shown in FIG.16. The measurement chamber may be coupled to process tool 348, as shownin FIG. 17. For example, the measurement chamber may be disposedlaterally or vertically proximate one or more process chambers ofprocess tool 348. In this manner, a robotic wafer handler of processtool 348, stage 354, or another suitable mechanical device may beconfigured to move specimen 352 to and from the measurement chamber andprocess chambers of the process tool. In addition, the robotic waferhandler, the stage, or another suitable mechanical device may beconfigured to move specimen 352 between process chambers of the processtool and the measurement chamber. Measurement device 346 may be furthercoupled to process tool 348 as further described with respect to FIG.17.

In an embodiment, stage 354 may be disposed within process tool 348.Stage 354 may be configured to support specimen 352 during a process. Inaddition, stage 354 may also be configured according to any of theembodiments described herein. For example, the stage may include amotorized stage that may be configured to rotate in a directionindicated by vector 356. Illumination system 358 of measurement device346 may be configured to direct light toward a surface of specimen 352.In addition, illumination system 358 may be configured to direct lighttoward a surface of the specimen during a process such as fabrication ofa portion of a semiconductor device and during rotation of the stage. Inaddition, a detection system of measurement device 346 may include afirst detector 360 and a second detector 362. Detectors 360 and 362 maybe configured to detect light propagating from the surface of thespecimen during a process such as fabrication of a portion of thesemiconductor device and during rotation of the stage.

As shown in FIG. 26, first detector 360 may be configured to detect darkfield light propagating along a dark field path from the surface ofspecimen 352. In addition, second detector 362 may be configured todetect bright field light propagating along a bright field path from thesurface of specimen 352. In this manner, light detected by themeasurement device may include dark field light propagating along a darkfield path from the surface of the specimen and bright field lightpropagating along a bright field path from the surface of the specimen.In addition, the detectors may be configured to substantiallysimultaneously detect light propagating from a surface of the specimen.

Furthermore, detected light may include dark field light propagatingalong multiple dark field paths from the surface of the specimen. Forexample, as shown in FIG. 27, a detection system of measurement device365 may include a plurality of detectors 366. The plurality of detectorsmay be positioned with respect to light source 368 such that each of theplurality of detectors may detect dark field light propagating from thesurface of the specimen. In addition, the plurality of detectors may bearranged at different radial and vertical positions with respect tolight source 368. A system that includes measurement device 365 may becommonly referred to as a “pixel-based” inspection system. Examples ofpixel-based inspection systems are illustrated in U.S. Pat. No.5,887,085 to Otsuka, and U.S. Pat. No. 6,081,325 to Leslie et al., andPCT Application No. WO 00/02037 to Smilansky et al., and areincorporated by reference as if fully set forth herein. An example of anoptical inspection method and apparatus utilizing a variable angledesign is illustrated in PCT Application No. WO 00/77500 A1 to Golberget al., and is incorporated by reference as if fully set forth herein.

As shown in FIG. 27, measurement device 365 may be further configured todirect light to multiple surfaces of specimen 370, which may be disposedupon a stage (not shown). The stage may be configured to move laterallyand/or rotatably with respect to measurement device 365 as describedherein. For example, the stage may be configured to move laterally whilelight from light source 368 may be configured to scan across thespecimen in a direction substantially parallel to a radius of thespecimen. Alternatively, the stage may be configured to move in twolinear directions, which may be substantially orthogonal to one another,and optical components of measurement device 365 may be substantiallystationary. The configuration of the stage with relation to the opticalcomponents of the measurement device may vary, however, depending upon,for example, space and mechanical constraints within the system. Lightsource 368 of measurement device may include any of the light sources asdescribed herein. In addition, fiber optic cable 372 or another suitablelight cable may be coupled to light source 368 and illumination system374 positioned below specimen 370. In this manner, the measurementdevice may be configured to direct light to multiple surfaces of aspecimen. In an alternative embodiment, measurement device 365 mayinclude at least two light sources. Each of the plurality of lightsources may be configured to direct light to a different surface of thespecimen.

Measurement device 365 may also include detector 376 coupled toillumination system 374. As shown in FIG. 27, detector 376 may bepositioned with respect to illumination system 374 such that thedetector may detect dark field light propagating along a dark fieldpath. In an alternative embodiment, however, detector 376 may bepositioned with respect to illumination 374 such that the detector maydetect bright field light propagating along a bright field path.Measurement device 346 and measurement device 365 may be furtherconfigured as according to any of the embodiments described herein.

The measurement device may be further configured according to any of theembodiments described herein. In addition, the system may include anadditional measurement device. The additional measurement device mayinclude any of the measurement devices as described herein.

In an embodiment, processor 364 coupled to measurement device 346 may beconfigured to determine one or more characteristics of defects on asurface of specimen 352, as shown in FIG. 26. In addition, processor 378coupled to measurement device 365 may be configured to determine one ormore characteristics of defects on one or more surfaces of specimen 370.Processor 364 and processor 378 may be similarly configured. Forexample, processors 364 and 378 may be configured to receive one or moreoutput signals from detectors 360 and 362 or 366 and 376, respectively,in response to light detected by the detectors. In addition, bothprocessors may be configured to determine at least one characteristic ofdefects on at least one surface of a specimen. The defects may includemacro defects and/or micro defects. For example, processor 264 andprocessor 378 may be configured to determine at least one characteristicof macro defects on a front side and a back side of a specimen. Inaddition, one or more characteristics of defects may include, but arenot limited to, a presence of defects on a surface of specimen, a typeof defects on a surface of a specimen, a number of defects on a surfaceof a specimen, and a location of defects on a surface of a specimen. Inaddition, processor 364 and processor 378 may be configured to determineone or more characteristics of defects substantially simultaneously orsequentially. In this manner, further description of processor 364 maybe applied equally to processor 378.

In an additional embodiment, processor 364 may be coupled to measurementdevice 346 and process tool 348. The process tool may include, forexample, a wafer cleaning tool such as a wet or dry cleaning tool, alaser cleaning tool, or a shock wave particle removal tool. An exampleof a laser cleaning tool is illustrated in “Chemically Assisted LaserRemoval of Photoresist and Particles from Semiconductor Wafers,” byGenut et al. of Oramir Semiconductor Equipment Ltd., Israel, presentedat the 28^(th) Annual Meeting of the Fine Particle Society, Apr. 1-3,1998, which are incorporated by reference as if fully set forth herein.An example of a shock wave particle removal method and apparatus isillustrated in U.S. Pat. No. 5,023,424 to Vaught, which is incorporatedby reference as if fully set forth herein. Processor 364 may beconfigured to interface with measurement device 346 and process tool348. For example, processor 364 may receive one or more output signalsfrom process tool 348 during a process that may be responsive to aparameter of an instrument coupled to the process tool. Processor 364may also be configured to receive one or more output signals frommeasurement device 346, which may be responsive to light detected bydetector 360 and detector 362 as described herein.

In an additional embodiment, the measurement device may be configured todetect light returned from the specimen during a process, as describedherein. For example, the measurement device may be configured to detectlight propagating from the specimen substantially continuously or atpredetermined time intervals during a process. The processor may,therefore, receive output signals from the measurement device inresponse to the detected light and may monitor variations in the outputsignals during a process. In this manner, processor 364 may beconfigured to determine a relationship between the output signals and aparameter of one or more instruments coupled to process tool 348. Assuch, processor 364 may be configured to alter a parameter of aninstrument coupled to the process tool in response to the determinedrelationship. In addition, the processor may be configured to determinea parameter of an instrument coupled to the process tool using therelationship and one or more output signals from the measurement device.

Additionally, processor 364 may be further configured to controlmeasurement device 346 and process tool 348. For example, the processormay be configured to alter a parameter of one or more instrumentscoupled to the process tool in response to output signals from themeasurement device. In this manner, the processor may be configured toalter a parameter of one or more instruments coupled to the process toolusing a feedback control technique, an in situ control technique, and/ora feedforward control technique. In addition, the processor may beconfigured to alter a parameter of an instrument coupled to themeasurement device in response to one or more output signals from themeasurement device. For example, the processor may be configured toalter a sampling frequency of the measurement device in response to theoutput signals.

By analyzing the variations in the output signals from the measurementdevice during a process, the processor may also generate a signaturethat may be characteristic of the process. The signature may include atleast one singularity that may be characteristic of an endpoint of theprocess. For example, an endpoint for a process may be a predeterminedthickness of a layer. A predetermined thickness of a layer on thespecimen may be larger or smaller depending upon, for example, asemiconductor device being fabricated on the specimen. After detectingthe singularity, the processor may reduce, and even terminate,processing of the specimen by altering a parameter of one or moreinstruments coupled to the process tool.

In an embodiment, the processor may be configured to determineparameters of one or more instruments coupled to the process tool forprocessing of additional specimens using output signals from themeasurement device. For example, a thickness of a layer on the specimenmay be determined using output signals from the measurement device. Thethickness of the layer on the specimen may be greater than apredetermined thickness. The predetermined thickness may vary dependingon, for example, a semiconductor device being fabricated on thespecimen. Before processing additional specimens, a parameter of one ormore instruments coupled to the process tool may be altered such that athickness of a layer on the additional specimens may be closer to thepredetermined thickness than a thickness of the layer on the measuredspecimen. For example, the radio frequency power of an etch process maybe increased to etch a greater thickness of the layer on the specimen.In this manner, the processor may be used to alter a parameter of one ormore instruments coupled to a process tool in response to output signalsfrom the measurement device using a feedback control technique.

In an additional embodiment, the processor may be configured todetermine process conditions of additional semiconductor fabricationprocesses using output signals from the measurement device. For example,the processor may be configured to alter a parameter of an instrumentcoupled to a stripping tool in response to output signals from themeasurement device using a feedforward control technique. In addition,the processor may be further configured according to the embodimentsdescribed herein.

In an embodiment, a method for determining a characteristic of aspecimen during a process may include disposing specimen 352 upon stage354. Stage 354 may be disposed within process tool 348. The stage mayalso be configured according to any of the embodiments described herein.Measurement device 346 may be coupled to process tool 348 as describedherein. As such, stage 354 may be coupled to measurement device 346. Inaddition, measurement device 346 may be configured as described herein.The method may include directing light to a surface of the specimenduring a process. In addition, the method may include detecting lightreturned from the surface of the specimen during a process. The methodmay also include generating one or more output signals in response tothe detected light. In this manner, the method may include determining acharacteristic of the specimen being processed using the one or moreoutput signals. The characteristic may include a presence, a number, alocation, and a type of defects on at least one surface of the specimen,or any combination thereof.

In additional embodiments, the method for determining a characteristicof a specimen during a process may include steps of any of theembodiments described herein. For example, the method may includealtering a parameter of an instrument coupled to the process tool inresponse to the one or more output signals. In this manner, the methodmay include altering a parameter of an instrument coupled to the processtool using a feedback control technique, an in situ control technique,and/or a feedforward control technique. In addition, the method mayinclude altering a parameter of an instrument coupled to the measurementdevice in response to the one or more output signals. For example, themethod may include altering a sampling frequency of the measurementdevice in response to the one or more output signals. Furthermore, themethod may include obtaining a signature characteristic of the process.The signature may include at least one singularity representative of anendpoint of the process. Subsequent to obtaining the singularityrepresentative of the endpoint, the method may include altering aparameter of one or more instruments coupled to the process tool toreduce, and even terminate, the process.

In an embodiment, a computer-implemented method may be used to control asystem configured to determine a characteristic of a specimen during aprocess. The system may include a measurement device coupled to aprocess tool as described herein. The method may include controlling themeasurement device to detect light returned from a surface of a specimenduring a process. For example, controlling the measurement device mayinclude controlling a light source to direct light to a surface of thespecimen during the process. In addition, controlling the measurementdevice may include controlling a detector configured to detect lightreturned from the surface of the specimen during the process. The methodmay also include generating one or more output signals in response tothe detected light. Furthermore, the method may include processing theone or more output signals to determine at least one characteristic ofdefects on at least one surface of the specimen using the one or moreoutput signals. The characteristics may also include any of thecharacteristics described herein.

In additional embodiments, the computer-implemented method forcontrolling a system to determine a characteristic of a specimen duringa process may include any steps of the embodiments described herein. Forexample, the method may include controlling one or more instrumentscoupled to the process tool to alter a parameter of the instruments inresponse to the one or more output signals. In this manner, the methodmay include controlling one or more instruments coupled to the processtool to alter a parameter of the instrument using a feedback controltechnique, an in situ control technique, and/or a feedforward controltechnique. In addition, the method may include controlling an instrumentcoupled to the measurement device to alter the parameter in response tothe one or more output signals. For example, the method may includecontrolling an instrument coupled to the measurement device to alter asampling frequency of the measurement device in response to the one ormore output signals.

In an additional example, the method may include controlling themeasurement device to obtain a signature characteristic of the process.The signature may include at least one singularity representative of anendpoint of the process. Subsequent to obtaining the singularityrepresentative of the endpoint, the method may include controlling aparameter of one or more instruments coupled to the process tool toalter a parameter of an instrument to reduce, and even stop, theprocess.

An additional embodiment relates to a method for fabricating asemiconductor device, which may include disposing a specimen upon astage. The stage may be disposed within a process tool. The stage may beconfigured as described herein. A measurement device may also be coupledto the process tool. In this manner, the stage may be coupled to themeasurement device. The method may further include forming a portion ofa semiconductor device upon the specimen. For example, forming a portionof a semiconductor device may include performing at least a step of asemiconductor fabrication process on the specimen. The method forfabricating a semiconductor device may also include directing light to asurface of the specimen. The method may further include detecting lightreturned from the surface of the specimen during the process. Inaddition, the method may include generating one or more output signalsin response to the detected light. Furthermore, the method may includedetermining at least one characteristic of the specimen from the one ormore output signals. The characteristic may include a presence, anumber, a type, or a location of defects on at least one surface of thespecimen, or any combination thereof.

In additional embodiments, the method for fabricating a semiconductordevice may include any steps of the embodiments described herein. Forexample, the method may include altering a parameter of one or moreinstruments coupled to the process tool in response to the one or moreoutput signals. In this manner, the method may include altering aparameter of one or more instruments coupled to the process tool using afeedback control technique, an in situ control technique, and/or afeedforward control technique. In addition, the method may includealtering a parameter of one or more instruments coupled to themeasurement device in response to the one or more output signals. Forexample, the method may include altering a sampling frequency of themeasurement device in response to the one or more output signals.Furthermore, the method may include obtaining a signature characteristicof the process. The signature may include at least one singularityrepresentative of an endpoint of the process. Subsequent to obtainingthe singularity representative of the endpoint, the method may includealtering a parameter of one or more instruments coupled to the processtool to reduce, and even terminate, the process.

In an embodiment, each of the systems describe above may be coupled toan energy dispersive X-ray spectroscopy (“EDS”) device. Such a devicemay be configured to direct a beam of electrons to a surface of thespecimen. The specimen may emit secondary electrons and a characteristicX-ray in response to the directed beam of electrons. The secondaryelectrons may be detected by a secondary electron detector and may beconverted to electrical signals. The electrical signals may be used forbrightness modulation or amplitude modulation of an image of thespecimen produced by the system. The characteristic X-ray may bedetected by a semiconductor X-ray detector and may be subjected toenergy analysis. The X-ray spectrum may be analyzed to determine acomposition of material on the specimen such as defects on a surface ofthe specimen. Examples of EDS systems and methods are illustrated inU.S. Pat. No. 4,559,450 to Robinson et al., U.S. Pat. No. 6,072,178 toMizuno, and U.S. Pat. No. 6,084,679 to Steffan et al., and areincorporated by reference as if fully set forth herein.

Further Improvements

In an embodiment, each of the systems, as described herein, may be usedto reduce, and even to minimize, within wafer (“WIW”) variability ofcritical metrics of a process such as a lithography process. Forexample, critical metrics of a lithography process may include aproperty such as, but are not limited to, critical dimensions offeatures formed by the lithography process and overlay misregistration.Critical metrics of a process, however, may also include any of theproperties as described herein including, but not limited to, a presenceof defects on the specimen, a thin film characteristic of the specimen,a flatness measurement of the specimen, an implant characteristic of thespecimen, an adhesion characteristic of the specimen, a concentration ofan elements in the specimen. Such systems, as described herein, may beconfigured to determine at least one property of a specimen at more thanone position on the specimen. For example, the measurement device may beconfigured to measure at least the one property of the specimen atmultiple positions within a field and/or at multiple positions within atleast two fields on the specimen. The measured property may be sent to aprocessor, or a within wafer film processor. The processor may becoupled to the measurement device and may be configured as describedherein.

In addition, because at least one property of the specimen may bemeasured at various positions across the specimen, at least one propertymay be determined for each of the various positions. As such, aparameter of one or more instruments coupled to a tool or a processchamber of a process tool may also be altered, as described above,independently from field to field on the specimen. For example, manyexposure process tools may be configured such that the exposure dose andfocus conditions of the expose process may be varied across thespecimen, i.e., from field to field. In this manner, process conditionssuch as exposure dose and/or post exposure bake temperature may varyacross the specimen in subsequent processes in response to variations inat least one measured property from field to field across the specimen.The exposure dose and focus conditions may be determined and/or alteredas described herein using a feedback or feedforward control technique.In this manner, critical metrics of a process such as a lithographyprocess may be substantially uniform across the specimen.

In addition, a temperature of the post exposure bake plate may bealtered across the bake plate by using a number of discrete secondaryheating elements disposed within a primary heating element. Secondaryheating elements may be independently controlled. As such, a temperatureprofile across a specimen during a post exposure bake process may bealtered such that individual fields on a specimen may be heated atsubstantially the same temperature or at individually determinedtemperatures. A pressure of a plating head of a chemical mechanicalpolishing tool may be similarly altered across the plate head inresponse to at least the two properties determined at multiple locationson the specimen.

In addition, at least the one parameter of a process chamber may bealtered such that a first portion of a specimen may be processed with afirst set of process conditions during a step of the process and suchthat a second portion of the specimen may be processed with a second setof process conditions during the step. For example, each portion of thespecimen may be a field of the specimen. In this manner, each field ofthe specimen may be subjected to different process conditions such as,but not limited to, exposure dose and focus conditions and post exposurebake temperatures. As such, because each field of a specimen may besubjected to process conditions that may vary depending upon a measuredproperty of the specimen, within wafer variations in critical metrics ofthe process may be substantially reduced, or even minimized.

It is to be understood that all of the measurements described above maybe used to alter a parameter of a process chamber using a feedback, afeedforward, or in situ process control technique. In addition, withinwafer variations of critical metrics of a process such as a lithographyprocess may be further reduced by using a combination of the abovetechniques.

A system configured to evaluate and control a process using field levelanalysis as described above may provide dramatic improvements overcurrent process control methods. Measuring within wafer variability ofcritical metrics, or critical dimensions, may provide tighter control ofthe critical dimension distribution. In addition to improving themanufacturing yield, therefore, the method described above may alsoenable a manufacturing process to locate the distribution performance ofmanufactured devices closer to a higher performance level. As such, thehigh margin product yield may also be improved by using such a method toevaluate and control a process. Furthermore, additional variations inthe process may also be minimized. For example, a process may use twodifferent, but substantially similarly configured process chambers, toprocess one lot of specimens. Two process chambers may be used toperform the same process such that two specimens may be processedsimultaneously in order to reduce the overall processing time.Therefore, the above method may be used to evaluate and control eachprocess chamber separately. As such, the overall process spread may alsobe reduced.

Data gathered using a system, as described herein, may be analyzed,organized and displayed by any suitable means. For example, the data maybe grouped across the specimen as a continuous function of radius,binned by radial range, binned by stepper field, by x-y position (orrange of x-y positions, such as on a grid), by nearest die, and/or othersuitable methods. The variation in data may be reported by standarddeviation from a mean value, a range of values, and/or any othersuitable statistical method.

The extent of the within wafer variation (such as the range, standarddeviation, and the like) may be analyzed as a function of specimen, lotand/or process conditions. For example, the within wafer standarddeviation of the measured CD may be analyzed for variation from lot tolot, wafer to wafer, and the like. It may also be grouped, reportedand/or analyzed as a function of variation in one or more processconditions, such as develop time, photolithographic exposure conditions,resist thickness, post exposure bake time and/or temperature,pre-exposure bake time and/or temperature, and the like. It may also orinstead be grouped, reported and/or analyzed as a function of withinwafer variation in one or more of such processing conditions.

Data gathered using a system, as described herein, may be used not justto better control process conditions, but also where desirable to bettercontrol in situ endpointing and/or process control techniques. Forexample, such data may be used in conjunction with an apparatus such asthat set forth in U.S. Pat. No. 5,689,614 to Gronet et al. and/orPublished European Patent Application No. EP 1 066 925 A2, which areincorporated by reference as if fully set forth herein, to improve thecontrol over localized heating of the substrate or closed loop controlalgorithms. Within wafer variation data may be fed forward or back tosuch a tool to optimize the algorithms used in control of local specimenheating or polishing, or even to optimize the tool design. In anotherexample of such localized process control, within wafer variation datamay be used to control or optimize a process or tool such as that setforth in one or more of Published PCT Patent Applications No. WO99/41434 or WO 99/25004 and/or Published European Patent Application No1065567 A2, which are hereby incorporated by reference as if fully setforth herein. Again, within wafer variation data taken, for example,from stand alone and/or integrated measurement tools, may be used tobetter control and/or optimize the algorithms, process parameters andintegrated process control apparatuses and methods in such tools orprocesses. Data regarding metal thickness and its within wafer variationmay be derived from an x-ray reflectance tool such as that disclosed inU.S. Pat. No. 5,619,548 and/or Published PCT Application No. WO01/09566, which are hereby incorporated by reference as if fully setforth herein, by eddy current measurements, by e-beam induced x-rayanalysis, or by any other suitable method.

As shown in FIG. 9, an embodiment of system 70 may have a plurality ofmeasurement devices. Each of the measurement devices may be configuredas described herein. As described above, each of the measurement devicesmay be configured to determine a different property of a specimen. Assuch, system 70 may be configured to determine at least four propertiesof a specimen. For example, measurement device 72 may be configured todetermine a critical dimension of a specimen. In addition, measurementdevice 74 may be configured to determine overlay misregistration of thespecimen. In an alternative embodiment, measurement device 76 may beconfigured to determine a presence of defects such as macro defects onthe specimen. In addition, measurement device 76 may be configured todetermine a number, a location, and/or a type of defects on thespecimen. Furthermore, measurement device 78 may be configured as todetermine one or more thin film characteristics of the specimen and/or alayer on the specimen. Examples of thin film characteristics include,but are not limited to, a thickness, an index of refraction, and anextinction coefficient. In addition, each of the measurement devices maybe configured to determine two or more properties of a specimen. Forexample, measurement device 72 may be configured to determine a criticaldimension and a thin film characteristic of a specimen substantiallysimultaneously or sequentially. In addition, measurement device 72 maybe configured to determine a presence of defects on the specimen. Assuch, system 70 may be configured to determine at least four propertiesof the specimen simultaneously or sequentially.

System 70 may be arranged as a cluster tool. An example of aconfiguration of a cluster tool is illustrated in FIG. 14. For example,each of the measurement devices described herein may be disposed in ameasurement chamber. Each of the measurement chambers may be disposedproximate one another and/or coupled to each other. In addition, system70 may include a wafer handler. The wafer handler may include anymechanical device as described herein. The system may be configured toreceive a plurality of specimen to be measured and/or inspected such asa cassette of wafers. The wafer handler may be configured to remove aspecimen from the cassette prior to measurement and/or inspection and todispose a specimen into the cassette subsequent to measurement and/orinspection. The wafer handler may also be configured to dispose aspecimen within each measurement chamber and to remove a specimen fromeach measurement chamber. In addition, the system may include aplurality of such wafer handlers. The system may be further configuredas described with reference to FIG. 14. In addition, the system may beconfigured as a stand-alone metrology and/or inspection system. In thismanner, the system may not be coupled to a process tool. Such a systemmay provide advantages over a similarly configured integrated tool. Forexample, such a system may be designed to be faster and cheaper than asimilarly configured integrated tool because there may be less physicaland mechanical constraints for a stand-alone system versus an integratedsystem. System 70 may be further configured as described herein.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including a thickness of a layer formed on thespecimen and at least one additional property such as an index ofrefraction, a velocity of sound, a density, and a critical dimension,which may include a profile, of a layer or a feature formed upon thespecimen. The specimen may include a structure such as single layer ormultiple layers formed upon the specimen. In addition, the single layeror multiple layers formed on the specimen may include, but are notlimited to, any combination of substantially transparent,semi-transparent, and opaque metal films. The specimen may also be ablanket wafer or a patterned wafer. As used herein, the term, “blanketwafer,” generally refers to a wafer having at least an upper layer thatmay not have been subjected to a lithography process. In contrast, asused herein, the term, “patterned wafer,” generally refers to a waferhaving at least an upper layer that may be patterned by, for example, alithography process and/or an etch process.

The system may be configured as described herein. For example, thesystem may include a processor coupled to two or more measurementdevices. The processor may be configured to determine at least athickness of the specimen and/or a layer on the specimen and at leastone additional property of the specimen and/or a layer on the specimenfrom one or more output signals generated by the measurement devices. Inaddition, the processor may be configured to determine other propertiesof the specimen from the one or more output signals. In an embodiment,the measurement device may include, but is not limited to, a small-spotphoto-acoustic device, a grazing X-ray reflectometer, and a broadbandsmall-spot spectroscopic ellipsometer. Examples of photo-acousticdevices are illustrated in U.S. Pat. No. 4,710,030 to Tauc et al., U.S.Pat. No. 5,748,318 to Maris et al., U.S. Pat. No. 5,844,684 to Maris etal., U.S. Pat. No. 5,684,393 to Maris, U.S. Pat. No. 5,959,735 to Mariset al., U.S. Pat. No. 6,008,906 to Maris. U.S. Pat. No. 6,025,918 toMaris, U.S. Pat. No. 6,175,416 to Maris et al., U.S. Pat. No. 6,191,855to Maris, U.S. Pat. No. 6,208,418 to Maris, U.S. Pat. No. 6,208,421 toMaris et al., and U.S. Pat. No. 6,211,961 to Maris, which areincorporated by reference as if fully set forth herein. The system mayalso include a pattern recognition system that may be used inconjunction with the above devices.

In this manner, the measurement device may be configured to function asa single measurement device or as multiple measurement devices. Becausemultiple measurement devices may be integrated into a single measurementdevice of the system, at least one element of a first measurementdevice, for example, may also be at least one element of a secondmeasurement device. In addition, it may be advantageous for additionalelements such as handling robots, stages, processors, and power suppliesof a first measurement device to be used by a second measurement device.The system may also include an autofocus mechanism that may beconfigured to bring a specimen substantially into focus (i.e., toapproximately a correct height) for a first measurement device, and thenfor a second measurement device. An example of an autofocus mechanism isshown in FIG. 11 b, as autofocus sensor 124. An additional example of anautofocusing apparatus is illustrated in U.S. Pat. No. 6,172,349 to Katzet al., which is incorporated by reference as if fully set forth herein.The system, the measurement device, and the processor may be furtherconfigured as described herein.

Appropriate combinations of devices included in the measurement devicemay include, for example, a small-spot photo-acoustic device and agrazing X-ray reflectometer or a small-spot photo-acoustic device and abroadband small-spot spectroscopic ellipsometer. For example, aphoto-acoustic device may provide measurements of layers havingthickness of less than about a few hundred angstroms while a grazingX-ray reflectometer may provide measurements of layers havingthicknesses in a range from about 50 angstroms to about 1000 angstroms.Ellipsometric techniques, especially broadband ellipsometry, may providemeasurements of metal and semi-metallic layers having thicknesses ofless than about 500 angstroms because at such thicknesses even metal mayallow some light to pass through the layer. In addition, ellipsometrictechniques may also provide measurements of transparent layers havingthicknesses from about 0 angstroms to a few microns. As such, a system,as described herein, may provide measurements of layers having a broadrange of thicknesses and materials.

In addition, such a system may be coupled to a chemical-mechanicalpolishing tool as described herein. Furthermore, the system may becoupled to or arranged proximate a chemical-mechanical polishing toolsuch that the system may determine at least two properties of aspecimen, a layer of a specimen, and/or a feature formed on the specimensubsequent to a chemical-mechanical polishing process. For example, afeature formed on the specimen may include a relatively wide metal line.Such a relatively wide metal line may include, for example, a teststructure formed on the specimen. In this manner, one or more of thedetermined properties of the test structure may be correlated(experimentally or theoretically) to one or more properties of a featuresuch as a device structure formed on the specimen. In addition, at leasta portion of the specimen may include an exposed dielectric layer.Alternatively, the system may be coupled to any other process tools asdescribed herein.

An appropriate spectroscopic ellipsometer may include a broadband lightsource, which may include one or a combination of light sources such asa xenon arc lamp, a quartz-halogen lamp, or a deuterium lamp. Theellipsometer may have a relatively high angle of incidence. For example,the angle of incidence may range from approximately 40 degrees toapproximately 80 degrees, to the normal to the surface of the specimen.The spectroscopic ellipsometer may include an array detector such as asilicon photodiode array or a CCD array, which may be back thinned.

It may also be advantageous for the spectroscopic ellipsometer toinclude one or more fiber optic elements. For example, a first fiberoptic element may be configured to transmit light from the light sourceto a first polarizing element. For example, such a fiber may ensure thatthe light is randomly polarized or depolarized. The spectroscopicellipsometer may also include a second fiber optic element configured totransmit light to a spectrometer from an analyzer assembly. In thismanner, the fiber optic element may be configured to alter, or“scramble,” a polarization state of light from the analyzer assemblysuch that the signal may not need correction for the polarizationsensitivity of the spectrometer. In addition, or alternatively, thesecond fiber optic element may be configured to alter the polarizationstate of the light such that the spectrometer may be convenientlylocated at some distance from the specimen. The fiber optic element may,preferably, be made of fused silica or sapphire such that the fiberoptic element may be transmissive at ultraviolet wavelengths.

The first polarizer may include a linear polarizing element such as aRochon prism or a Wollaston prism and, optionally, a retarder (i.e., acompensator). The analyzer assembly may include a linear polarizingelement and, optionally, a retarder. At least one of the linearpolarizing elements may rotate continuously when making measurements.For calibration, at least two elements will be rotated eithercontinuously or in a series of discrete steps.

The spectroscopic ellipsometer may further include reflective orrefractive optics (or combinations thereof) configured to focus thelight to a small spot on the specimen and to collect the light from thespecimen. Any refractive components may, preferably, be made from fusedSiO₂ or CaF₂ for relatively good ultraviolet transmission. Anyreflective components may, preferably, be coated with Al for relativelygood broadband transmission. Typically, a thin overcoat of MgF₂ or SiO₂may be formed over the Al to reduce, and even eliminate, oxidation ofthe Al. The reflective components may be spherical or aspherical.Diamond turning may be a convenient and well-known technique for makingaspheric mirrors. For vacuum conditions such as conditions suitable forultraviolet light having wavelengths in a range of less than about 190nm, gold or platinum may be a suitable coating material. Thespectroscopic ellipsometer may be further configured as describedherein.

In an embodiment, a spectroscopic ellipsometer may be coupled to alithography track. The lithography track may be configured asillustrated in FIG. 13 and as described herein. The spectroscopicellipsometer may be configured as in any of the embodiments describedherein. A processor may be coupled to the spectroscopic ellipsometer.The processor may be configured to determine at least one property ofthe specimen including, but not limited to, a critical dimension, aprofile, a thickness or other thin film characteristics of the specimen,a layer formed on the specimen, and/or a feature formed on the specimenfrom one or more output signals generated by the spectroscopicellipsometer. In addition, the spectroscopic ellipsometer may be coupledto the lithography track as described herein. For example, thespectroscopic ellipsometer may be coupled to a process chamber of thelithography track such that the spectroscopic ellipsometer may directlight toward and detect light returned from a specimen on a supportdevice in the process chamber. In addition, the spectroscopicellipsometer may be configured to direct light toward and detect lightreturned from the specimen while the support device is spinning.Furthermore, the spectroscopic ellipsometer may be configured to directlight toward and detect light returned from the specimen during aprocess being performed in the process chamber. The process may include,but is not limited to, a resist apply process, a post apply bakeprocess, and a chill process.

Alternatively, the spectroscopic ellipsometer may be disposed within thelithography track. For example, the spectroscopic ellipsometer may bedisposed above a chill chamber, in an integration system, or laterallyproximate or vertically proximate to a process chamber of thelithography track. An integration system may be configured to couple alithography track to an exposure tool. For example, the integrationsystem may be configured to receive a specimen from the lithographytrack and to send the specimen to the exposure tool. In addition, theintegration system may be configured to receive or remove a specimenfrom the exposure tool and to send the specimen to the lithographytrack. The integration system may also include one or more chill platesand a handling robot. In this manner, the system may be configured todetermine at least one property of the specimen at various points in alithography process such as prior to an exposure step, subsequent to theexposure step, and subsequent to a develop step of the process.

The spectroscopic ellipsometer may or may not be disposed within ameasurement chamber as described above. For example, in an alternativeembodiment, the spectroscopic ellipsometer may be coupled to a roboticwafer handler of the lithography track. In this manner, thespectroscopic ellipsometer may be configured to direct light toward anddetect light returned from the specimen prior to or subsequent to aprocess such as prior to exposure, subsequent to exposure, or afterdevelop. For example, subsequent to exposure, the spectroscopicellipsometer may be configured to generate one or more output signalsresponsive to a critical dimension, a profile, a thickness or other thinfilm characteristics of a latent image formed on the specimen by theexposure process.

An environment within the track may be controlled by chemical filtrationof atmospheric air or by feeding a supply of sufficiently pure gas. Forexample, the environment within the track may be controlled such thatlevels of chemical species including, but not limited to, ammonia andamine-group-containing compounds, water, carbon dioxide, and oxygen maybe reduced. In addition, the environment within the track may becontrolled by a controller computer such as controller computer 162, asillustrated in FIG. 14 coupled to the ISP system. The controllercomputer may be further configured to control additional environmentalconditions within the track including, but not limited to, relativehumidity, particulate count, and temperature.

The spectroscopic ellipsometer may be configured as described herein.For example, an appropriate spectroscopic ellipsometer may include abroadband light source, which may include one or a combination of lightsources such as a xenon arc lamp, a quartz-halogen lamp, or a deuteriumlamp. The ellipsometer may have a relatively high angle of incidence.For example, the angle of incidence may range from approximately 40degrees to approximately 80 degrees, to the normal to the surface of thespecimen. The spectroscopic ellipsometer may include an array detectorsuch as a silicon photodiode array or a CCD array, which may be backthinned.

It may also be advantageous for the spectroscopic ellipsometer toinclude one or more fiber optic elements. For example, a first fiberoptic element may be configured to transmit light from the light sourceto a first polarizing element. For example, such a fiber may ensure thatthe light is randomly polarized or depolarized. The spectroscopicellipsometer may also include a second fiber optic element configured totransmit light to a spectrometer from an analyzer assembly. In thismanner, the fiber optic element may be configured to alter, or“scramble,” a polarization state of light from the analyzer assemblysuch that the signal may not need correction for the polarizationsensitivity of the spectrometer. In addition, or alternatively, thesecond fiber optic element may be configured to alter the polarizationstate of the light such that the spectrometer may be convenientlylocated at some distance from the specimen. The fiber optic element may,preferably, be made of fused silica or sapphire such that the fiberoptic element may be transmissive at ultraviolet wavelengths.

The first polarizer may include a linear polarizing element such as aRochon prism or a Wollaston prism and, optionally, a retarder (i.e., acompensator). The analyzer assembly may include a linear polarizingelement and, optionally, a retarder. At least one of the linearpolarizing elements may rotate continuously when making measurements.For calibration, at least two elements will be rotated eithercontinuously or in a series of discrete steps.

The spectroscopic ellipsometer may further include reflective orrefractive optics (or combinations thereof) configured to focus thelight to a small spot on the specimen and to collect the light from thespecimen. Any refractive components may, preferably, be made from fusedSiO₂ or CaF₂ for relatively good ultraviolet transmission. Anyreflective components may, preferably, be coated with Al for relativelygood broadband transmission. Typically, a thin overcoat of MgF₂ or SiO₂may be formed over the Al to reduce, and even eliminate, oxidation ofthe Al. The reflective components may be spherical or aspherical.Diamond turning may be a convenient and well-known technique for makingaspheric mirrors. For vacuum conditions such as conditions suitable forultraviolet light having wavelengths in a range of less than about 190nm, gold or platinum may be a suitable coating material. Thespectroscopic ellipsometer may be further configured as describedherein.

In addition, the processor may be configured to compare one or moreoutput signals from the spectroscopic ellipsometer with one or morepredetermined tables that may include expected output signals versuswavelength for different characteristics and, possibly, interpolateddata between the expected output signals versus wavelength.Alternatively, the processor may be configured to perform an iterationusing one or more starting guesses through (possibly approximate)equations to converge to a good fit for one or more output signals fromthe spectroscopic ellipsometer. Suitable equations may include, but arenot limited to, any non-linear regression algorithm known in the art.

Alternatively, the spectroscopic ellipsometer may be configured to imageapproximately all, or an area of, a specimen onto a one-dimensional ortwo-dimensional detector. In this manner, multiple locations on thespecimen may be measured substantially simultaneously. In addition, thespectroscopic ellipsometer may be configured to measure multiplewavelengths by sequentially changing wavelength with filters, amonochromator, or by dispersing the light. For example, the light may bedispersed with a prism or grating in one dimension on a two-dimensionaldetector while one dimension of the specimen is being imaged in theother dimension.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including a thickness of the specimen and/or alayer formed on the specimen, a feature formed on the specimen and anadditional property such as a lattice constant, residual stress, averagegrain size, crystallinity, crystal defects, an index of refraction, avelocity of sound, a density, and a critical dimension, which mayinclude a profile, of a layer or a feature formed upon the specimen. Thespecimen may include a single layer or multiple layers formed upon thespecimen. In addition, the single layer or multiple layers formed on thespecimen may include, but are not limited to, any combination oftransparent, semi-transparent, and opaque metal films. The specimen mayalso be a blanket wafer or a patterned wafer.

The system may be configured as described herein. For example, thesystem may include a processor coupled to a measurement device andconfigured to determine at least a thickness of the specimen and/or alayer on the specimen and an additional property of a layer on thespecimen and/or a feature formed on the specimen from one or more outputsignals generated by the measurement device. In addition, the processormay be configured to determine other properties of the specimen from theone or more output signals. In an embodiment, the measurement device mayinclude, but is not limited to, a grazing X-ray reflectometer, an X-rayreflectometer such as a grating X-ray reflectometer, and/or an X-raydiffractometer. The measurement device may also include a patternrecognition system that may be used in conjunction with the abovedevices.

An X-ray reflectometer may be configured to perform an X-ray reflectancetechnique as described herein.

An X-ray diffractometer may be configured to perform X-ray diffraction.X-ray diffraction involves coherent scattering of x-rays bypolycrystalline materials. The x-rays are scattered by each set oflattice planes at a characteristic angle, and the scattered intensity isa function of the atoms which occupy those planes. X-ray diffractionpeaks may be produced by constructive interference of a monochromaticbeam scattered from each set of lattice planes at specific angles. Thepeak intensities are determined by atomic arrangement within the latticeplanes. In this manner, the scattering from all the different sets ofplanes results in a pattern, which is unique to a given compound. Inaddition, distortions in the lattice planes due to stress, solidsolution, or other effects may be measured. The scattered x-rays may bedetected and one or more output signals responsive to the intensity ofthe scattered x-rays may be generated. The one or more output signalsmay be used to obtain one or more properties of a layer on a specimen ora specimen. An advantage of X-ray diffraction is that it is asubstantially non-destructive technique. Commercially available X-raydiffractometers are available from, for example, Siemens, Madison, Wis.and Rigaku USA, Inc., The Woodlands, Tex.

In an embodiment, an X-ray diffractometer may be coupled to a processtool configured to grow an epitaxial layer of silicon on a specimen suchas a wafer. Epitaxy is a process in which a relatively thin crystallinelayer is grown on a crystalline substrate. An epitaxial layer ofsilicon, which may be commonly referred to as “epitaxy” or “epi,” may bea layer of extremely pure silicon or silicon-germanium formed on asilicon containing substrate. The layer may be grown to form asubstantially uniform crystalline structure on the wafer. In epitaxialgrowth, the substrate acts as a seed crystal, and the epitaxial filmduplicates the structure (orientation) of the crystal. Epitaxialtechniques include, but are not limited to, vapor-phase epitaxy,liquid-phase epitaxy, solid-phase epitaxy, and molecular beam epitaxy. Athickness of the epitaxial layer during an epitaxy process (i.e., agrowth rate) may vary over time depending upon, for example, chemicalsource, deposition temperature, and mole fraction of the reactants.Examples of appropriate chemical sources include, but are not limitedto, silicon tetrachloride (“SiCl₄”), trichlorosilane (“SiHCl₃”),dichlorosilane (“SiH₂Cl₂”), and silane (“SiH₄”). Examples of appropriatetemperatures for an epitaxy process may range from about 950° C. toabout 1250° C. An appropriate temperature may be higher or lower,however, depending upon, for example, the chemical source used for theepitaxy process. Such process tools are commercially available fromApplied Materials, Inc., Santa Clara, Calif. The X-ray diffractometermay be configured as described above.

The X-ray diffractometer may be coupled to the process tool according toany of the embodiments described herein. For example, an X-raydiffractometer may be coupled to a process chamber of the epitaxialprocess tool or may be disposed proximate to the process chamber in ameasurement chamber. In addition, a processor may be coupled to theX-ray diffractometer and the process tool. The processor may be furtherconfigured as described above.

In this manner, the measurement device may be configured to function asa single measurement device or as multiple measurement devices. Becausemultiple measurement devices may be integrated into a single measurementdevice of the system, elements of a first measurement device, forexample, may also be elements of a second measurement device. Inaddition, it may be advantageous for additional elements such ashandling robots, stages, processors, and power supplies of a firstmeasurement device to be used by a second measurement device. Themeasurement device may also include an autofocus mechanism that may beconfigured to bring a specimen substantially into focus (i.e., toapproximately a correct height) for a first measurement device, and thenfor a second measurement device. The system, the measurement device, theautofocus mechanism, and the processor may be further configured asdescribed herein.

In addition, such a system may be coupled to a process tool including,but not limited to, a chemical-mechanical polishing tool, a depositiontool such as a physical vapor deposition tool, a plating tool, and anetch tool. The system may be coupled to the process tool as describedherein. Furthermore, the system may be coupled to or disposed proximateto a process tool such that the system may determine at least twoproperties of a specimen, a layer of a specimen, and/or a feature formedon the specimen prior to, during, or subsequent to a process.

In an embodiment, a system may be configured to determine at least twoproperties of a specimen including an electrical property such as acapacitance, a dielectric constant, and a resistivity of the specimenand/or a layer on the specimen and a thin film characteristic of thespecimen and/or a layer on the specimen. The thin film characteristicmay include any of the characteristics as described herein. The specimenmay include a wafer or a dielectric material disposed upon a wafer oranother substrate. Examples of appropriate dielectric materials include,but are not limited to, gate dielectric materials and low-k dielectricmaterials. Typically, low-k dielectric materials include materialshaving a dielectric constant less than about 3.8, and high-k materialsinclude materials having a dielectric constant greater than about 4.5.

The system may be configured as described herein. For example, thesystem may include a processor coupled to a first measurement device anda second measurement device and configured to determine at least a thinfilm characteristic of the specimen and/or a layer on the specimen fromone or more output signals of the first measurement device and anelectrical property of the specimen and/or a layer on the specimen froman output signal of the second measurement device. In addition, theprocessor may be configured to determine other properties of thespecimen from the one or more output signals. For example, the processormay also be used to determine additional properties of the specimenincluding, but not limited to, a characteristic of metal contaminationon the specimen. In an embodiment, the first measurement device mayinclude, but is not limited to, a reflectometer, a spectroscopicreflectometer, an ellipsometer, a spectroscopic ellipsometer, a beamprofile ellipsometer, a photo-acoustic device, an eddy current device,an X-ray reflectometer, a grazing X-ray reflectometer, and an X-raydiffractometer and a system configured to measure an electrical propertyof the specimen. The system, the first measurement device, and theprocessor may be further configured as described herein.

Such a system may be coupled to a process tool such as a deposition toolincluding, but not limited to, a chemical vapor deposition tool, anatomic layer deposition tool and a physical vapor deposition tool, aplating tool, a chemical-mechanical polishing tool, a thermal tool suchas a furnace, a cleaning tool, and an ion implanter, as describedherein. Such a system may also be coupled to an etch tool. In thismanner, at least the two properties may be used to determine an amountof plasma damage caused to the specimen and/or a layer on the specimenduring an etch process performed by the etch tool. For example, plasmadamage may include, but is not limited to, roughness and pitting of aspecimen or a layer on a specimen generated during an etch process.

The second measurement device may be configured to measure an electricalproperty of the specimen as illustrated, for example, in U.S. patentapplication Ser. No. 09/854,177 entitled “A Method Of Detecting MetalContamination On A Semiconductor Wafer.” by Xu et al., filed May 10,2001, issued as U.S. Pat. No. 6,759,255 on Jul. 6, 2004, which isincorporated by reference as if fully set forth herein. For example, aspecimen may be placed into a wafer cassette, which may be loaded intothe system. The system may include a robotic handler, which may beconfigured as described herein. The system may also include apre-aligner that may be configured to alter a position of a specimen.For example, a pre-aligner may be configured to alter a position of thespecimens such the orientation of each specimen may be substantially thesame during processing. Alternatively, the pre-aligner may be configuredto detect an alignment mark formed on a specimen and to alter a positionof the specimen such that a position of the alignment mark may besubstantially the same as a predetermined position.

In an embodiment, the second measurement device may also include an oventhat may be used to anneal a specimen. The oven may be configured toheat the specimen to a temperature, for example, of less thanapproximately 1100° C. The oven may also be configured to drive themetal contamination into a dielectric material of the specimen or into asemiconductor substrate of the specimen. The second measurement devicemay also include a cooling device configured to reduce a temperature ofthe specimen subsequent to the annealing process. The cooling device mayinclude any such device known in the art such as a chill plate.

In an embodiment, the second measurement device may include a deviceconfigured to deposit a charge on an upper surface of the specimen. Thedevice may include, for example, a non-contact corona charging devicesuch as a needle corona source or a wire corona source. Additionalexamples of non-contact corona charging devices are illustrated in U.S.Pat. No. 4,599,558 to Castellano et al., U.S. Pat. No. 5,594,247 toVerkuil et al., U.S. Pat. No. 5,644,223 to Verkuil, and U.S. Pat. No.6,191,605 to Miller et al., which are incorporated by reference as iffully set forth herein. The deposited charge may be positive or negativedepending on the parameters of the device used to deposit the charge.The device may be used to deposit a charge on predetermined regions ofthe specimen or on randomly determined regions of the specimen. Inaddition, the device may also be used to deposit a charge on a portionof the specimen or on substantially the entire specimen.

In an embodiment, the second measurement device may also include asensor configured to measure at least one electrical property of thecharged upper surface of the specimen. The sensor may be configured tooperate as a non-contact work function sensor or a surface photo-voltagesensor. The non-contact work function sensor may include, e.g., a Kelvinprobe sensor or a Monroe sensor. Additional examples of work functionsensors, which may be incorporated into the system, are illustrated inU.S. Pat. No. 4,812,756 to Curtis et al., U.S. Pat. No. 5,485,091 toVerkuil, U.S. Pat. No. 5,650,731 to Fung, and U.S. Pat. No. 5,767,693 toVerkuil and are incorporated by reference as if fully set forth herein.The sensor may be used to measure electrical properties, which mayinclude, but are not limited to, a tunneling voltage, a surface voltage,and a surface voltage as a function of time. The second measurementdevice may also include an illumination system that may be configured todirect a pulse of light toward the specimen and that may be used togenerate a surface photo-voltage of the specimen. As such, an electricalproperty that may be measured by the sensor may also include a surfacephoto-voltage of the specimen. The system may further include a movablechuck configured to alter a position of the specimen under the device,under the illumination system, and under the sensor. As such, the secondmeasurement device may be used to measure an electrical property of thespecimen as a function of time and position of the specimen.

In an additional embodiment, the system may also include a processorthat may be configured as described herein and may be used to monitorand control operation of the oven to heat the specimen to an annealtemperature. The processor may also be configured to monitor and controlthe operation of the device to deposit a charge on an upper surface ofthe specimen. Additionally, the processor may be further configured tomonitor and control the operation of the sensor to measure an electricalproperty of the specimen. The measured electrical property may include asurface voltage of a dielectric material formed on the specimen, whichmay be measured as a function of time. The second measurement device maybe configured to generate one or more output signals responsive to themeasured electrical property. The processor may be configured to use oneor more output signals from the second measurement device to determineat least one property of the specimen such as a resistivity of thedielectric material. The resistivity of the dielectric material may bedetermined by using the following equation:

ρ_(dielectric) =−V/[(dV/dt)·∈·∈₀],

where Σ_(dielectric) is the resistivity of the dielectric material, V isthe measured surface voltage of the dielectric material, i is the decaytime, ∈ is the dielectric constant of the dielectric material, and ∈₀ isthe vacuum permittivity. A characteristic of metal contamination in thedielectric material may also be a function of the resistivity of thedielectric material.

Furthermore, the processor may be used to determine a characteristic ofthe metal contamination in the specimen. The characteristic of the metalcontamination in the specimen may be determined as a function of themeasured electrical property. In addition, the processor may also beconfigured to monitor and control an additional device of the operatingsystem including, but not limited to, a robotic wafer handler, apre-aligner, a wafer chuck, and/or an illumination system.

In an embodiment, each of the systems described above may be coupled toa secondary electron spectroscopy device. Such a system may beconfigured to determine material composition of a specimen by analyzingsecondary electron emission from the specimen. An example of such adevice is illustrated in PCT Application No. WO 00/70646 to Shachal etal., and is incorporated by reference as if fully set forth herein.

In an additional embodiment, more than one system described herein maybe coupled to a semiconductor fabrication process tool. Each of thesystems may be configured to determine at least two properties of aspecimen during use. Furthermore, each of the systems may be configuredto determine at least two substantially similar properties or at leasttwo different properties. In this manner, properties of a plurality ofspecimens may be determined substantially simultaneously and at multiplepoints throughout a semiconductor fabrication process.

In a further embodiment, each of the systems described herein may becoupled to a stand alone metrology and/or inspection system. Forexample, each of the systems described herein may be coupled to a standalone metrology and/or inspection system such that signals such asanalog or digital signals may be sent between the coupled systems. Eachof the systems may be configured as a single tool or a cluster tool thatmay or may not be coupled to a process tool such as a semiconductorfabrication process tool. The stand alone metrology and/or inspectionsystem may be configured such that the stand alone system may becalibrated with a calibration standard. An appropriate calibrationstandard may include any calibration standard known in the art. Thestand alone metrology and/or inspection system may be configured tocalibrate the system coupled to the stand alone system.

In addition, the stand alone metrology and/or inspection system may becoupled to a plurality of systems as described herein. In this manner,the stand alone metrology and/or inspection system may be configured tocalibrate the plurality of systems coupled to the stand alone system.For example, a plurality of systems may include single tools and/orcluster tools incorporated within the same manufacturing and/or researchand development facility. Each of the plurality of systems may beconfigured to determine at least two characteristics of a specimen. Inaddition, each of the plurality of systems may be configured todetermine at least two characteristics of substantially the same type ofspecimen such as specimens upon which a substantially similar type ofsemiconductor device may be formed. For example, each of the pluralityof systems may be incorporated into the same type of product line in amanufacturing facility.

In addition, the stand alone metrology and/or inspection system may beconfigured to calibrate each of the plurality of systems using the samecalibration standard. As such, a plurality of metrology and/orinspection systems in a manufacturing and/or research and developmentfacility may be calibrated using the same calibration standard. Inaddition, the stand alone metrology and/or inspection system may beconfigured to generate a set of data. The set of data may include outputsignals from a measurement device of a system and characteristics of aspecimen determined by a processor of the system using the outputsignals. The set of data may also include output signals and determinedcharacteristics corresponding to the output signals that may begenerated by using a plurality of systems as described herein.Therefore, the set of data may be used to calibrate and/or monitor theperformance of a plurality of systems.

In an additional embodiment, each of the systems, as described herein,may be coupled to a cleaning tool. A cleaning tool may include any toolconfigured to remove unwanted material from a wafer such as a drycleaning tool, a wet cleaning tool, a laser cleaning tool, and/or ashock wave cleaning tool. A dry cleaning tool may include a dry etchtool, which may be configured to expose a specimen to a plasma. Forexample, resist may be stripped from a specimen using an oxygen plasmain a plasma etch tool. An appropriate plasma may vary depending upon,for example, the type of material to be stripped from a specimen. Theplasma etch tool may be further configured as described herein. Drycleaning tools are commercially available from, for example, AppliedMaterials, Inc., Santa Clara, Calif. A wet cleaning tool may beconfigured to submerge a specimen in a chemical solution, which mayinclude, but is not limited to, a sulfuric-acid mixture or ahydrofluoric acid mixture. Subsequent to exposure to the chemicalsolution, the specimen may be rinsed with de-ionized water and dried.Wet cleaning tools are commercially available from, for example, FSIInternational, Inc., Chaska, Minn. An example of a laser cleaning toolis illustrated in “Chemically Assisted Laser Removal of Photoresist andParticles from Semiconductor Wafers,” by Genut et al. of OramirSemiconductor Equipment Ltd., Israel, presented at the 28^(th) AnnualMeeting of the Fine Particle Society, Apr. 1-3, 1998, which areincorporated by reference as if fully set forth herein. An example of ashock wave cleaning tool is illustrated in U.S. Pat. No. 5,023,424 toVaught, which is incorporated by reference as if fully set forth herein.

In a further embodiment, each of the systems, as described herein, maybe coupled to a thermal tool such as a tool configured for rapid thermalprocessing (“RTP”) of a wafer. A rapid thermal processing tool may beconfigured to subject a specimen to a relatively brief, yet highlycontrolled thermal cycle. For example, the RTP tool may be configured toheat a specimen to over approximately 1000° C. in under approximately 10seconds. RTP may be used mainly for modifying properties of a specimenor a film formed on a specimen formed by other processes. For example,RTP may be commonly used for annealing, which may activate and controlthe movement of atoms in a specimen after implanting. Another common useis for silicidation, which may form silicon-containing compounds withmetals such as tungsten or titanium. A third type of RTP application isoxidation, which may involve growing oxide on a specimen such as asilicon wafer. RTP tools are commercially available from, for example,Applied Materials, Inc., Santa Clara, Calif.

In an embodiment, each of the processors described above including alocal processor, a remote controller computer, or a remote controllercomputer coupled to a local processor may be configured to perform acomputer integrated manufacturing technique as illustrated in EuropeanPatent Application EP 1 072 967 A2 to Arackaparambil et al., which isincorporated by reference as if fully set forth herein.

In a further embodiment, each of the processors as described herein maybe configured to automatically generate a schedule for wafer processingwithin a multichamber semiconductor wafer processing tool as illustratedin U.S. Pat. No. 6,201,999 to Jevtic, U.S. Pat. No. 6,224,638 to Jevtic,and PCT Application No. WO 98/57358 to Jevtic, which are incorporated byreference as if fully set forth herein. In addition, each of the systemsas described herein may include a multiple blade wafer handler. Aprocessor as described herein may be configured to control the multipleblade wafer handler. Each of the processors as described herein may beconfigured to assign a priority value to process chambers and/ormeasurement chambers of a cluster tool such as a process tool or ameasurement and/or inspection system. One or more measurement chambersmay be coupled to a process tool according to any of the embodiments asdescribed herein. Each of the processors as described herein may also beconfigured to assign a priority to measurement chambers of a clustertool such as a metrology and/or inspection system.

The processor may be configured to control the multiple blade waferhandler such that the multiple blade wafer handler may be configured tomove a specimen from chamber to chamber according to the assignedpriorities. The processor may also be configured to determine an amountof time available before a priority move is to be performed. If thedetermined amount of time is sufficient before a priority move is to beperformed, the processor may control the multiple blade wafer handler toperform a non-priority move while waiting. For example, if thedetermined amount of time is sufficient before a process step is to beperformed on a specimen, then the multiple blade wafer handler may movethe specimen to a measurement chamber. In this manner, a system asdescribed herein may be configured to determine at least two propertiesof a specimen while the specimen is waiting between process steps. Theprocessor may also be configured to dynamically vary assigned prioritiesdepending upon, for example, the availability of process and/ormeasurement chambers. Furthermore, the processor may assign prioritiesto the process and/or measurement chambers based upon, for example, atime required for a wafer handler to move the wafer in a particularsequence.

In addition, each of the processors as described herein may beconfigured to use “options,” which may correspond to optional componentsof a process tool, and which may be selected by a user according to theoptional components that the user desires to have as part of the processtool as illustrated in U.S. Pat. No. 6,199,157 to Dov et al., which isincorporated by reference as if fully set forth herein.

A process tool as described herein may also include multiple chillprocess chambers or a multi-slot chill process chamber. Such multiple ormulti-slot chill process chambers allows multiple wafers to be cooledwhile other wafers are subjected to processing steps in other chambers.In addition, each of the processors as described herein may beconfigured to assign a priority level to each wafer in a processingsequence depending on its processing stage, and this priority level maybe used to sequence the movement of wafers between chambers asillustrated in U.S. Pat. No. 6,201,998 to Lin et al., which isincorporated by reference as if fully set forth herein. In this manner,a system as described herein may increase an efficiency at which wafersare transferred among different processing chambers in a waferprocessing facility.

In a further embodiment, each of the processors, as described herein,may be configured to determine at least a roughness of a specimen, alayer on a specimen, and/or a feature of a specimen. For example, aprocessor may be configured to determine a roughness from one or moreoutput signals of a measurement device using mathematical modeling. Forexample, the one or more output signals may be generated by ameasurement device such as a non-imaging scatterometer, a scatterometer,a spectroscopic scatterometer, and a non-imaging Linnik microscope.Appropriate mathematical models may include any mathematical modelsknown in the art such as mathematical models that may be used todetermine a critical dimension of a feature. The mathematical models maybe configured to process data of multiple wavelengths or data of asingle wavelength.

A system, including such a processor, may be coupled to a process toolsuch as a lithography tool, an atomic layer deposition tool, a cleaningtool, and an etch tool. For example, a develop process step in alithography process may cause a significant amount of roughness to apatterned resist. In addition, a layer of material formed by atomiclayer deposition may have a significant amount of roughness,particularly on sidewalls of features on a specimen. Furthermore, wetcleaning tools may tend to etch a specimen, a layer on a specimen,and/or features on a specimen, which may cause roughness on thespecimen, the layer, and/or the features, respectively. The system mayalso be coupled to any process tool configured to perform a process thatmay cause roughness on a surface of a specimen. The system may becoupled to the process tool according to any of the embodimentsdescribed herein. For example, a measurement device of such a system maybe coupled to a process chamber of a process tool such that the systemmay determine at least a roughness of a specimen, a layer on a specimen,and/or a feature on a specimen prior to and subsequent to a process. Forexample, the measurement device may be coupled to a process tool suchthat a robotic wafer handler may move below or above the measurementdevice. The system may be further configured as described herein.

The following references, to the extent that they provide exemplaryprocedural or other information or details supplementary to those setforth herein, are specifically incorporated herein by reference: U.S.patent application Ser. No. 09/310,017 filed on May 11, 1999, issued asU.S. Pat. No. 6,268,916 on Jul. 31, 2001 to Lee et al., U.S. patentapplication Ser. No. 09/396,143 filed on Sep. 15, 1999, issued as U.S.Pat. No. 6,628,397 on Sep. 30, 2003 to Nikoonahad et al., U.S. patentapplication Ser. No. 09/556,238 filed on Apr. 24, 2000, issued as U.S.Pat. No. 6,671,051 on Dec. 30, 2003 to Nikoonahad et al., and Ser. No.09/695,726 filed on Oct. 23, 2000, issued as U.S. Pat. No. 6,787,773 onSep. 7, 2004 to Lee.

Further modifications and alternative embodiments of various aspects ofthe invention may be apparent to those skilled in the art in view ofthis description. For example, the system may also include a stageconfigured to tilt in a number of angles and directions with respect toa measurement device. Accordingly, this description is to be construedas illustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as the presently preferred embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims.

What is claimed is:
 1. A system configured to determine a property of aspecimen, comprising: a scatterometer configured to direct light towardrepeatable pattern features on a surface of the specimen, wherein thescatterometer comprises a spectrometer configured to measure diffractionorder intensities of different wavelengths of light diffracted from therepeatable pattern features, and wherein the diffraction orderintensities comprise diffraction order intensities higher than thezeroth diffraction order intensity; and a processor coupled to thespectrometer and configured to determine a property of the repeatablepattern features using output of the spectrometer responsive to themeasured diffraction order intensities.